Looking for some insight here...
On my form, I have three ComboBox controls. When the left most receives a selection, it calls a routine to enable and populate the 2nd, then the same happens for the 3rd when a selection is made in the 2nd.
Private Sub cboEquipment_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles cboEquipment.SelectedIndexChanged
Me.transData.isMobile = If(Me.cboEquipment.Text = MOBIEQIP, 1, 0)
If cboMembership.Enabled = False Then
Me.cboMembership.Enabled = True
End If
Call loadGroups()
End Sub
The method 'loadGroups'
Private Sub loadGroups()
Dim cn As New SqlConnection(My.Settings.MyConnectionString)
Dim cm As New SqlCommand("SELECT ... ORDER BY codeHumanName ASC", cn)
Dim ta As New SqlDataAdapter(cm)
Dim dt As New DataTable
Me.cboMembership.DataSource = Nothing
Me.cboMembership.Items.Clear()
Me.transData.membership = Nothing
cn.Open()
ta.Fill(dt)
With Me.cboMembership
.DataSource = dt
.DisplayMember = "codeHumanName"
.ValueMember = "codeID"
End With
cn.Close()
End Sub
This works fine an dandy, everything loads at should, and provides the appropriate .ValueMember results.
I should mention that when the Form first loads, boxes 2 and 3 are empty and disabled. After their initial load, I have to select an item from the list to get values (as expected).
The odd part is that once the 2nd or 3rd Combobox have been 'initialized', they seem to recall last settings. For example, if I call the Reset method, which sets the .DataSource property to Nothing, clear the list, and set the Text to Nothing; the next time I change the SelectedIndex on cboEquipment, the other boxes come back to life with SelectedItems and SelectedValues.
These values aren't wrong according to the new DataTable, but it is odd that they remember at all (they shouldn't have any reference, and behave as a fresh load).
Other points of interest; the populate methods are called during the SelectedIndexChanged event.
Any thoughts would be great!
UPDATE -
This behavior is tied in with the SelectedIndexChange Event bouncing around (raise! raise! raise!)
Removing and adding event handlers at strategic points has my code working as I want/expect it to.
Here is the article that put me on the right path...
On your second and third combo boxes try clearing the .Text/.SelectedText properties before you set the .DataTable
The combo box is probably just being too helpful and assuming that when you set the .DataTable a second time, you'd want the selected item to match your .Text property.
I ended up using AddHandler and RemoveHandler to prevent chain-firing events as the comboboxes were being populated.
Related
I have two forms which are connected, the first one has a datagridview(DGV) that will show list of staff.
When I double click the row the data from the FGV will transfer into second form for user to edit the data. Each column from the DGV will insert at textbox combobox etc.
But the combobox on second form are using database when I double click the DGV; the others is fine but for combobox it will show the first data in database.
This is the code for the double click on the first form:
Private Sub DataGridView1_CellDoubleClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellDoubleClick
Dim frmEdit As New Edit
frmEdit.lblEENo.Text = DataGridView1.CurrentRow.Cells(1).Value.ToString
frmEdit.txtName.Text = DataGridView1.CurrentRow.Cells(2).Value.ToString
frmEdit.txtAge.Text = DataGridView1.CurrentRow.Cells(3).Value.ToString
frmEdit.lblAgeCategory.Text = DataGridView1.CurrentRow.Cells(4).Value.ToString
frmEdit.txtGender.Text = DataGridView1.CurrentRow.Cells(5).Value.ToString
frmEdit.cbEthnicity.Text = DataGridView1.CurrentRow.Cells(6).Value.ToString
frmEdit.cbGrade.Text = DataGridView1.CurrentRow.Cells(7).Value.ToString
frmEdit.cbCategory.Text = DataGridView1.CurrentRow.Cells(8).Value.ToString
frmEdit.cbDepartment.Text = DataGridView1.CurrentRow.Cells(9).Value.ToString
frmEdit.cbPosition.Text = DataGridView1.CurrentRow.Cells(10).Value.ToString
frmEdit.txtReporting.Text = DataGridView1.CurrentRow.Cells(11).Value.ToString
frmEdit.DateTimePicker1.Value = DataGridView1.CurrentRow.Cells(12).Value.ToString
frmEdit.DateTimePicker2.Value = DataGridView1.CurrentRow.Cells(13).Value.ToString
If DataGridView1.CurrentRow.Cells(14).Value.ToString = "Y" Then
frmEdit.rbYes.Checked = True
ElseIf DataGridView1.CurrentRow.Cells(14).Value.ToString = "N" Then
frmEdit.rbNo.Checked = True
End If
frmEdit.cbStatus.Text = DataGridView1.CurrentRow.Cells(15).Value.ToString
frmEdit.txtNote.Text = DataGridView1.CurrentRow.Cells(16).Value.ToString
frmEdit.lblMody.Text = tslblLoginAs.Text
frmEdit.ShowDialog()
load_data()
End Sub
This is second form's code for connecting to the database table for the combobox:
Private Sub Edit_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim frmMasterList As New MasterStaff
Dim poscmd As New SqlCommand("SELECT * from MasterPositionList", conn)
Dim posadapt As New SqlDataAdapter(poscmd)
Dim postable As New DataTable
posadapt.Fill(postable)
cbPosition.DataSource = postable
cbPosition.DisplayMember = "PositionName"
Dim depcmd As New SqlCommand("SELECT * from MasterDepartmentList", conn)
Dim depadapt As New SqlDataAdapter(depcmd)
Dim deptable As New DataTable
depadapt.Fill(deptable)
cbDepartment.DataSource = deptable
cbDepartment.DisplayMember = "DeparmentName"
End Sub
The form load event fires too late to populate the combobox. The event is raised almost immediately when you create the form instance in the DataGridView1_CellDoubleClick() method, but the event handler can't actually run until control is returned to the messaging loop, and there's no chance for that to happen until the frmEdit.ShowDialog() line, which is after you have set the combobox values. Therefore the Load event runs after you have populated your desired value and will overwrite that work.
To fix this, move that Load code to the constructor, just after the InitializeComponent() method.
Additionally, since you want to select from the items provided by the database you should look at using the SelectedItem or SelectedValue property, instead of the Text property.
Finally, it's really poor practice to reuse the same connection object throughout an application or form. Yes, database connections are expensive objects to create and manage, but the ADO.Net library already handles this for you. The SqlConnection object you work with in code is a light-weight wrapper over a pool of the more-expensive actual raw connections. When you try to reuse one SqlConnection, you gain efficiency in the cheap thing while losing efficiency in the more expensive thing.
Instead, create (and promptly Dispose()!) a new SqlConnection object every time you need to use the database, and think about reducing connections by reducing round-trips to the database. In this case, you can combine the two SELECT statements into a single string and fill two DataTables in the same database trip:
Private Sub New ' Replaces the current Edit_Load() method
InitializeComponent()
Dim results As New DataSet
'Using block will make sure the connection is closed, **even if an exception is thrown**
' Do NOT(!) try to reuse the connection. Only reuse the connection string.
Using conn As New SqlConnection(connString), _
' Two SELECT queries in one string
cmd As New SqlCommand("SELECT * from MasterPositionList;SELECT * from MasterDepartmentList", conn), _
da As New DataAdapter(cmd)
da.Fill(results)
End Using 'Dispose the database objects as quickly as possible
cbPosition.DisplayMember = "PositionName"
cbDepartment.DisplayMember = "DeparmentName"
cbPosition.DataSource = results.Tables(0) 'Filled two tables in one database call
cbDepartment.DataSource = results.Tables(1)
End Sub
I am wondering why you need a separate form when you could edit the data directly in the DGV. When you think of it, all the data you're trying to edit is already found in the DGV (or should exist in its datasource). You can even have combo boxes inside the DGV, with their own bound datatables. Here is an example that shows how it could be done.
In Edit_Load there is unnecessary repetition. You load the same dataset twice. You could reuse it or even load it at startup and keep it in cache if it's not changing during application runtime.
Plus, rather than fetch values from the DGV, it would better to fetch the selected datarow instead. For this you just need the record ID...
There is no need to access UI attributes, use the underlying datatable instead.
You shouldn't be using index numbers. Imagine the mess and potential for bugs if you want to insert columns or move columns. Also, the user probably can reorder columns in the DGV by drag & drop... thus your logic is ruined and the program will not behave like it should.
Anyway, to answer your issue: you've loaded a datatable, now all you have to do is bind it to the combo (which you did). You have used the DataSource and DisplayMember attributes. You could use SelectedValue to preselect a value in the list like this:
With cbPosition
.DisplayMember = "PositionName"
.ValueMember = "PositionName"
.SelectedValue = "The text value that comes from the DGV"
.DataSource = postable
End With
As long as the value from the DGV is present in the datatable this should work.
Again, I think you should simplify your UI. All the data could be edited in-place in the DGV.
VB.net app changes values in a datagridview programmatically. The values are all as they should be, but the save routine (dtShipments is the datatable that is the source for the datagridview)
Dim dtChanges As DataTable = dtShipments.getchanges()
If more than one has changed, dtChanges is always missing the last row.
In the routine that changes the cell values, I have tried DatagridView1.EndEdit and DatagridView1.CommitEdit, but the behavior is the same. I even tried adding a SendKeys.Send(vbTab) line, since hitting the tab key when making the changes manually is enough to get all the changes to show up in .GetChanges.
What am I missing?
code per request:
Private Sub btnAssign_Click(sender As Object, e As EventArgs) Handles btnAssign.Click
strModErr = "Form1_btnAssign_Click"
Dim sTruck As String = ""
Try
sTruck = Me.DataGridView2.SelectedCells(0).Value.ToString
For Each row As DataGridViewRow In DataGridView1.SelectedRows
row.Cells("Truck").Value = sTruck
Next
DataGridView1.CommitEdit(DataGridViewDataErrorContexts.Commit)
Catch ex As Exception
WriteErrorToLog(Err.Number, strModErr + " - " + Err.Description)
End Try
End Sub
Private Function SaveChanges() As Boolean
strModErr = "Form1_SaveChanges"
Dim Conn As New SqlConnection(My.Settings.SQLConnectionString)
Dim sSQL As String = "UPDATE fs_Shipments SET Truck = #Truck, Stop = #Stop WHERE SalesOrder = #SO"
Dim cmd As New SqlCommand(sSQL, Conn)
Dim sSO, sTruck As String
Dim iStop As Integer = 0
Try
DataGridView1.EndEdit()
DataGridView1.ClearSelection()
Dim dtChanges As DataTable = dtShipments.getchanges() 'DataRowState.Modified
If Not dtChanges Is Nothing Then
Conn.Open()
For Each row As DataRow In dtChanges.Rows
sSO = row("SalesOrder").ToString
sTruck = row("Truck").ToString
iStop = CInt(row("Stop").ToString)
With cmd.Parameters
.Clear()
.AddWithValue("#SO", sSO)
.AddWithValue("#Truck", sTruck)
.AddWithValue("#Stop", iStop)
End With
cmd.ExecuteNonQuery()
Next
End If
Return True
Catch ex As Exception
WriteErrorToLog(Err.Number, strModErr + " - " + Err.Description)
Return False
End Try
End Function
I am not exactly 100% sure why this happens. The problem appears to be specific to when the user “selects” the cells in the first grid, and then calls the SaveChanges code “BEFORE” the user has made another selection in the first grid. In other words, if the user “selects” the rows to “assign” the truck to in grid 1, then, “AFTER” the “selected” cells have been filled with the selected truck, THEN, the user selects some other cell in grid 1, THEN calls the save changes code. In that case the code works as expected.
All my attempts at committing the changes, either failed or introduced other issues. I am confident a lot of this has to do with the grids SelectedRows collection. IMHO, this looks like a risky way to set the cell values, I would think a more user-friendly approach may be to add a check box on each row and assign the truck values to the rows that are checked. But this is an opinion.
Anyway, after multiple attempts, the solution I came up with only further demonstrates why using a BindingSource is useful in many ways. In this case, it appears the DataTable is not getting updated with the last cell change. Again, I am not sure “why” this is, however since it appears to work using a BindingSource, I can only assume it has something to do with the DataTable itself. In other words, before the “Save” code is executed, we could call the tables AcceptChanges method, but then we would lose those changes. So that is not an option.
To help, below is a full (no-fluff) example. In the future, I highly recommend you pull out the parts of the code that do NOT pertain to the question. Example, all the code that saves the changes to the DB is superfluous in relation to the question… so remove it. The more unnecessary code you add to your question only increases the number of SO users that will “ignore” the question. If you post minimal, complete and working code that reproduces the problem so that users can simply copy and paste without having to add addition code or remove unnecessary code will increase you chances of getting a good answer. Just a heads up for the future.
The solution below simply adds a BindingSource. The BindingSource’s DataSource is the DataTable dtShipments then the BindingSource is used a DataSource to DataGridView1. Then in the SaveChanges method, “before” the code calls the dtShipment.GetChanges() method, we will call the BindingSources.ResetBinding() method which should complete the edits to the underlying data source, in this case the DataTable dtShipments.
If you create a new VS-VB winforms solution, drop two (2) grids and two (2) buttons onto the form as shown below, then change the button names to “btnAssign” and “btnApplyChanges.” The assign button will add the selected truck in grid two to the selected rows in grid one. The apply changes button simply resets the binding source and displays a message box with the number of rows that were changed in the dtShipments DataTable. It should be noted, that the code calls the dtShipments.AcceptChanges() method to clear the changes. Otherwise, the code will update changes that have already been made.
Dim dtShipments As DataTable
Dim dtTrucks As DataTable
Dim shipBS As BindingSource
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
dtShipments = GetShipmentsDT()
shipBS = New BindingSource()
shipBS.DataSource = dtShipments
dtTrucks = GetTrucksDT()
dtShipments.AcceptChanges()
DataGridView1.DataSource = shipBS
DataGridView2.DataSource = dtTrucks
End Sub
Private Function GetShipmentsDT() As DataTable
Dim dt = New DataTable()
dt.Columns.Add("ID", GetType(String))
dt.Columns.Add("Truck", GetType(String))
dt.Rows.Add(1)
dt.Rows.Add(2)
dt.Rows.Add(3)
dt.Rows.Add(4)
Return dt
End Function
Private Function GetTrucksDT() As DataTable
Dim dt = New DataTable()
dt.Columns.Add("Truck", GetType(String))
For index = 1 To 10
dt.Rows.Add("Truck" + index.ToString())
Next
Return dt
End Function
Private Sub btnAssign_Click(sender As Object, e As EventArgs) Handles btnAssign.Click
Dim sTruck = DataGridView2.SelectedCells(0).Value.ToString
'Dim drv As DataRowView
For Each row As DataGridViewRow In DataGridView1.SelectedRows
'drv = row.DataBoundItem
'drv("Truck") = sTruck
row.Cells("Truck").Value = sTruck
Next
'DataGridView1.CommitEdit(DataGridViewDataErrorContexts.Commit)
'shipBS.ResetBindings(True)
'DataGridView1.CurrentCell = DataGridView1.Rows(0).Cells(0)
End Sub
Private Function SaveChanges() As Boolean
Try
shipBS.ResetBindings(True)
Dim dtChanges As DataTable = dtShipments.GetChanges()
If (dtChanges IsNot Nothing) Then
MessageBox.Show("There are " & dtChanges.Rows.Count & " rows changed in the data table")
' update sql DB
dtShipments.AcceptChanges()
End If
Return True
Catch ex As Exception
Return False
End Try
End Function
Private Sub btnApplyChanges_Click(sender As Object, e As EventArgs) Handles btnApplyChanges.Click
Dim ChangesMade As Boolean
ChangesMade = SaveChanges()
End Sub
Lastly, since you are using VB… I highly recommend that you set the “Strict” option to “ON.” When this option is ON, it will flag possible errors that you may be missing. To do this for all future VB solutions, open VS, close any solutions that may be open, then go to Tools->Options->Projects and Solutions->VB Defaults, then set “Option Strict” to “On.” The default setting is off.
I hope this makes sense and helps.
I need to add several bits of data to my record such as created date and createdby when a user adds a new row in a datatable.
I am looking for the correct event on the bindingsource to catch this so i can add the information then save the record before the user moves onto the next row.
C# seems to have a RowEditEnding event on the datagrid but a)i'm not using C# and b) I can see from searching that its better to work on the datasource, which in this case is a bound datagrid so i presume i should be looking at the bindingsource object but there is not an obvious event to choose.
I think need something like currentchanged with condition if isdirty then...
Please can someone point me in the right direction here.
thanks
john
this seems to work
Private Sub TblOppQuoteDetailBindingSource_CurrentChanged(sender As Object, e As EventArgs) Handles TblOppQuoteDetailBindingSource.CurrentChanged
If sender.current IsNot Nothing Then
If sender.current.IsNew Then
Dim nr As DataRowView = sender.current
nr.Item("OppQuoteID") = 2
nr.Item("Created") = Now
nr.Item("CreatedBy") = G_UserName
ElseIf sender.current.isedit Then
Dim nr As DataRowView = sender.current
nr.Item("OppQuoteID") = 2
nr.Item("Updated") = Now
nr.Item("UpdatedBy") = G_UserName
End If
End If
End Sub
is this the correct way?
GD All,
I've looking around for a solution to my below challenge.
I have got a form with an unbound datagridview, the dg has one added column that allows user to select a method to be used.
The state of the event is stored in a database and after re-opening the form the code checks if the event is in an 'open' state, if so it compares the previously selected method with the methods in the datagrid and should set the previously activated method to be the 'selected' method.
Yet I can't seem to get this to work unfortunately...
The below code loops through the methods in the dg and compares the values, if it meets the methodID it should set the value to 'True' or to the TrueValue anyway.
This is initialized if the database check returns true and after full initialisation of the form, where session.methodID is a field in the returned LINQ query.
For Each r As DataGridViewRow In dgMethods.Rows
If r.Cells(1).Value = session.methodID Then
Dim c As DataGridViewCheckBoxCell = r.Cells(0)
c.Value = c.TrueValue
End If
Next
Unfortunately, this doesn't set the checkbox to 'Checked'.
The loop runs and evaluates the comparison between r.Cells(1).Value and session.methodID correct and triggers correctly.
The interesting thing is if I do a similar loop after the 'CellContentClick' event it does do exactly what is expected. (the example below sets all checkbox values to checked)
Private Sub dgMethods_CellContentClick(sender As Object, e As DataGridViewCellEventArgs) Handles dgMethods.CellContentClick
'Only single selection allowed, so clear table before submitting new selection
For Each r As DataGridViewRow In dgMethods.Rows
Dim c As DataGridViewCheckBoxCell = r.Cells(0)
c.Value = c.TrueValue
Next
dgMethods.CommitEdit(DataGridViewDataErrorContexts.Commit)
End Sub
So, apparently there is a difference in the state between just calling the loop on the dgMethods and when the dgMethods.CellContentClick event has triggered, yet I do not know which one ?
There are many many post on trying to set the CheckBox column yet I have not been able to get any of them working.
Anybody have any idea ?
I would appreciate your suggestions ?
I was not sure of being undestand your question... but there's s simple way to check and change the state of a chechbox cell in a datagridview:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
For Each dr As DataGridViewRow In DataGridView1.Rows
If CBool(dr.Cells(0).Value) = True Then dr.Cells(0).Value = False : Continue For
If CBool(dr.Cells(0).Value) = False Then dr.Cells(0).Value = True
Next
End Sub
In this example, when you click this button for each row in the datagridview, checks the checkboxcell and set the value to FALSE or TRUE depending of his value.
Hope this helps you.
And let me one more tip. If you get acces to the cells for his name instead of his index use his name, it should helps you avoiding troubles ;)
GD All,
After searching further I came across the following interesting behaviour.
The method selection process is part of a form called 'frmAddEvent', the frmAddEvent form is called from a main form using below routine.
The new form instance is created and afterwards filled using a public sub in the form class called InitializeForm() which uses a GUID parameter to retrieve corresponding data to set the form fields.
If Not (isOpened(rsTankName.unqID)) Then
Dim newForm As New frmAddEvent() '(rsTankName)
newForm.InitializeForm(rsTankName)
newForm.Show()
Else
End If
The initialization sub queries several datatables and sets the corresponding fields in the new form instance correctly if applicable.
Part of that setting is the method selection in the dgMethods datagridview.
It would appear that the sequence in which you call the form makes all the difference as the below code works perfectly:
If Not (isOpened(rsTankName.unqID)) Then
Dim newForm As New frmAddEvent() '(rsTankName)
newForm.Show()
newForm.InitializeForm(rsTankName)
Else
End If
So calling the newForm.InitializeForm(rsTankName)after the newForm.Show event allows the datagridview to set the CheckBoxColumn correctly.
Likely because the actual CheckBox itself is only actually generated upon the Show command, despite the fact that it is 'available' as a cell with DataGridViewCheckBoxColumn properties in the datagrid, directly after the New frmAddEvent has created the new form instance. The actual CheckBox and its corresponding CheckedState is not created before the newForm.Show event is called. It would appear that the when the CheckBox is created for display (during the newForm.Show event) there is no comparison made to its actual value.
So, in order to set the Checkbox column on initiating a new form you have to call the Show event prior to setting the DataGridViewCheckBoxColumn values otherwise the CheckBox will not show it as 'Checked'.
I am trying to show a DataGridView in a form that is bound to a DataTable, but it's not showing up. I was doing this using a C1TrueDBGrid and that was working...I decided to switch to using a DataGridView due to some complications with the TrueDBGrid. Can anyone help me figure out why nothing is showing?
In the form I declare these:
Public binData As DataSet
Friend WithEvents dgvData As System.Windows.Forms.DataGridView
The binData is filled with tables created via a separate calculation routine. Then this is the form load event:
'create a tab page and add data grid view for every table in the set
For i = 0 To binData.Tables.Count - 1
Dim tabPage As C1.Win.C1Command.C1DockingTabPage = New C1.Win.C1Command.C1DockingTabPage
tabPage.Text = binData.Tables(i).TableName
tabContent.TabPages.Add(tabPage)
Dim dgvData = New System.Windows.Forms.DataGridView
Dim binding As New BindingSource
binding.DataSource = binData.Tables(i)
With dgvData
.Dock = DockStyle.Fill
.AllowUserToOrderColumns = False
.AllowUserToAddRows = False
.AllowUserToDeleteRows = False
.DefaultCellStyle.Alignment = DataGridViewContentAlignment.BottomLeft
.DataSource = binding
.AutoGenerateColumns = True
End With
tabPage.Controls.Add(dgvData)
Next 'DataTable In binData.Tables
When the form loads, the tab pages are there and labeled as expected, but they look empty (no table).
I did try instead setting the DataSource to the DataSet called binData (as opposed to a specific table), and then setting dgvData's DataMember property to the name of the specific table I want to display in it...that made no difference.
Note: I need to be able to do this programmatically at runtime as opposed to using the visual designer because I do not know the exact number of grids I need until the form loads with a particular dataset - the dataset it gets can have a different number of tables depending on what the user wants.
Here's some rough code to add dgvs to a flow panel:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Static dgvCount As Integer
dgvCount += 1
Dim dgvNew As New DataGridView
dgvNew.Width = DataGridView1.Width
dgvNew.Height = DataGridView1.Height
dgvNew.Name = "dgv" & dgvCount
' clone other properties as need
FlowLayoutPanel1.Controls.Add(dgvNew)
Debug.Print(FlowLayoutPanel1.Controls(FlowLayoutPanel1.Controls.Count - 1).Name)
End Sub
Starts with one dgv - DataGridView1 as the model for properties. Anchoring is not working in the flow panel so some custom code may be need to change width.
Flow panel doesn't scroll so may not be the best choice - look into TableLayout as a possibility. TabControl is another option.
OK, well it turns out there was nothing wrong with what I was doing. The issue turned out to be in one line of code that has nothing to do with binding the DGV's datasource or anything.
ComponentOne has a control called a ThemeController in which you can set themes for your forms and the controls within. I had a line of code to set the theme for dgvData to my default application theme (which sets visual style and details regarding colors, fonts, etc.). For whatever reason, THAT was rendering my grid non-visible. I will be logging a ticket with them.