I have problems trying to change programmatically the content of a cell of a bound DataGridView.
I implemented a minimal piece of code to show the problem.
Do the following steps to replicate the problem:
Launch example
Write the title content to create a new row
CTRL+C on inserted title
Move to grid's empty row to force the creation of a new row
CTRL+V on title cell
Click on previous row (new row creation is cancelled)
Click again to the empty row to force the creation of a new row
Exception: Operation is not valid due to the current state of the object.
Here it is the code:
Public Class Form1
Private _dgv As New DataGridView
Private _Movies As New System.ComponentModel.BindingList(Of Movie)
Public Sub New()
InitializeComponent()
Me.Controls.Add(_dgv)
_dgv.Dock = DockStyle.Fill
_dgv.DataSource = _Movies
AddHandler _dgv.KeyDown, AddressOf DataGridView_KeyDown
End Sub
Private Sub DataGridView_KeyDown(sender As Object, e As KeyEventArgs)
If e.Control AndAlso e.KeyCode = Keys.V Then
_dgv.CurrentCell.Value = Clipboard.GetText
End If
End Sub
Public Class Movie
Public Property Title As String
End Class
End Class
For sure there is something wrong in my implementation but I spent many hours searching a workaround without success. Thank you in advance for any help you can give me.
When setting up the form in the constructor, make sure the EditMode of the DataGridView is DataGridViewEditMode.EditOnEnter. This makes the cell we are pasting to enter edit mode as soon as it receives focus and makes the new row stick instead of being cancelled if we move away from it.
Public Sub New()
InitializeComponent()
Me.Controls.Add(_dgv)
_dgv.Dock = DockStyle.Fill
_dgv.DataSource = _Movies
AddHandler _dgv.KeyDown, AddressOf DataGridView_KeyDown
_dgv.EditMode = DataGridViewEditMode.EditOnEnter
End Sub
Then, instead of setting the cell value, set the Title property of the underlying Movie:
Private Sub DataGridView_KeyDown(ByVal sender As Object, ByVal e As KeyEventArgs)
If e.Control AndAlso e.KeyCode = Keys.V Then
Dim Mov As Movie = _Movies.Last
Mov.Title = Clipboard.GetText
_dgv.Refresh()
End If
End Sub
When you add a new row in the DataGridView, the BindingList is automagically adding a new Movie object to the list. _Movies.Last should gets you the newly added Movie.
Why not use the DataGridView event UserAddedRow?
system.windows.forms.datagridview.useraddedrow
Related
I'm building a form that has many buttons, all buttons do the same thing: add 1 every time they are clicked. Every pressed button is sent to a datagridview along with the time they are pressed. Datagrid values look like this:
a_1_serv (button name), 18:05:00(time).
Sometimes I want to delete the last row. Everything works fine so far.
When I delete the last row, I want to change the text of the button (a_1_serv).
I can parse the dgv value (a_1_serv) to a variable but I can't bind it to the appropriate button name so I can control it.
Is there a way to do it?
Don't store your program state in your UI
Create a data structure to hold the information, and let the DataGridView be a "view", not treating it as a variable. You will save yourself headaches vs using the UI as a variable.
That said, create a class to represent your information
Public Class Data
Public Sub New(button As Button, time As DateTime)
Me.Button = button
Me.Time = time
End Sub
<System.ComponentModel.Browsable(False)>
Public Property Button As Button
Public ReadOnly Property Text As String
Get
Return Button.Name
End Get
End Property
Public Property Time As DateTime
End Class
And your code can manipulate the data in a variable off the UI. Bind the data to the DataGridView for display.
Private datas As New List(Of Data)()
Private Sub Button_Click(sender As Object, e As EventArgs) Handles Button1.Click, Button2.Click, Button3.Click, Button4.Click
addButton(DirectCast(sender, Button))
End Sub
Private Sub RemoveLastButton_Click(sender As Object, e As EventArgs) Handles RemoveLastButton.Click
removeLast()
End Sub
Private Sub addButton(b As Button)
datas.Add(New Data(b, DateTime.Now))
bindData()
End Sub
Private Sub removeLast()
Dim b = datas.Last.Button
b.Text = "new text" ' change to whatever
datas.RemoveAt(datas.Count - 1)
bindData()
End Sub
Private Sub bindData()
DataGridView1.DataSource = Nothing
DataGridView1.DataSource = datas
End Sub
This does exactly what you stated but there may be inconsistency in these two bits of information you provided: a_1_serv (button name) and I want to change the text of the button .... This changes the button text but not the name. The name is displayed in the grid. You can change the data class to display the text or whatever. But the point is this approach will keep your data off the UI and you won't need to look up the control by name anymore.
I've created a UserControl and added it to a FlowLayoutPanel. The UserControl is being used to allow a user to enter a material, cost and delivery status to the form. When the user has filled it in, I want another UserControl to appear underneath it in the FlowLayoutPanel
The UserControl simply generates a string based on the text entered into two TextBox controls and the status of two Checkbox controls. it also has a property that indicates when the user has filled in enough information. I want to use this property to signal generating a new UserControl.
At the moment I have my first UserControl on the FlowLayoutPanel, it is successfully passing the String and CreateNew property back.
The problems I am encountering are:
How do I monitor to see if CreateNew has changed to True?
How do I add a control to the form and +1 to the controls name for future referencing
Once the new control is added, I need to monitor to see if the new CreateNew state changes to repeat the cycle
Can anyone point me in the right direction here, there's a lot of information out there on this, but I can't seem to find anything useful from other's problems/questions.
UPDATE 1
Thanks to user Zaggler for the comment, I have now managed to get the control to create a new instance of itself on the FlowLayoutPanel. But now I'm faced with a new problem of it only creating one new usercontrol, then it stops.
Here's the code I'm using:
UserControl Code
Public Class Alv_Product_Order_Control
Public OutString As String
Public Event CreateNew()
Dim CreateNewRaised As Boolean
Private Sub OutputString(sender As Object, e As EventArgs) Handles tbMaterial.TextChanged, tbCost.TextChanged,
cbDelivered.CheckedChanged, cbOrderPlaced.CheckedChanged
OutString = "¦¦" & tbMaterial.Text & "¦" & tbCost.Text & "¦"
If cbOrderPlaced.Checked = True Then
OutString = OutString & "Yes¦"
Else
OutString = OutString & "No¦"
End If
If cbDelivered.Checked = True Then
OutString = OutString & "Yes¦"
Else
OutString = OutString & "No¦"
End If
If tbCost.Text = "" Or tbMaterial.Text = "" Then
Else
If CreateNewRaised = False Then
RaiseEvent CreateNew() 'Raise the event that's used to signal adding a new control to the layout
CreateNewRaised = True 'Create A Latched Boolean that cannot change again in the future
End If
End If
End Sub
Public ReadOnly Property Alv_Product_Order_Control As String
Get
Return OutString 'Pass string back to main form
End Get
End Property
Main Form Code
Private Sub CreateSecondPOC() Handles POC1.CreateNew
FlowLayoutPanel1.Controls.Add(New Alveare_VB.Alv_Product_Order_Control)
End Sub
I'm guessing here that the problem is the CreateSecondPOC only handles the event for the the first POC1
How do I create a new Alveare_VB.Alv_Product_Order_Control, name it as POC2 and also add a handler to handle POC2.CreateNew and add another control?
Edit 2
I know I've found the answer, but i'd like to look at this memory leak that has been mentioned. I've changed the code supplied in the answer below to this:
Private Sub CreateSecondPOC(ByVal sender As Object, ByVal e As System.EventArgs) Handles POC1.CreateNew
Try
Dim oldPoc = DirectCast(sender, Alveare_VB.Alv_Product_Order_Control)
RemoveHandler oldPoc.CreateNew, AddressOf CreateSecondPOC
Catch ex As Exception
Debug.Print(ex.Message)
End Try
Dim newPoc As New Alveare_VB.Alv_Product_Order_Control
AddHandler newPoc.CreateNew, AddressOf CreateSecondPOC
FlowLayoutPanel1.Controls.Add(newPoc)
End Sub
And I get the following error on the "RemoveHandler" line:
Unable to cast object of type 'System.Windows.Forms.TextBox' to type 'Alveare_VB.Alv_Product_Order_Control'.
The CreateNew event is raised when a textbox is written in, this is getting passed back as the sender I assume? Not really sure where to go with this now.
Edit 3
The error was in my UserControl, I was sending the incorrect object back (in this case the textbox). I have now changed the RaiseEvent to return the UserControl as an object. Now all is working correctly.
You could change your handler to something like this
Private Sub CreateSecondPOC() Handles POC1.CreateNew
Dim newPoc As New Alveare_VB.Alv_Product_Order_Control
AddHandler newPoc.CreateNew, AddressOf CreateSecondPOC
FlowLayoutPanel1.Controls.Add(newPoc)
End Sub
I'm not sure if you want to keep handling the event, even after it has been populated once, i.e. can it be depopulated, then repopulated, then raise the event again? Maybe you want to lock it once it's populated, but this isn't clear.
You could also keep all your POC controls in a container and only create a new one when they are all populated.
Edit:
According to comments below, you should remove the event handler when you no longer need it in order to avoid memory leaks. Here is one way
Private Sub CreateSecondPOC(sender As Object) Handles POC1.CreateNew
Dim oldPoc = DirectCast(sender, Alveare_VB.Alv_Product_Order_Control)
RemoveHandler oldPoc, AddressOf CreateSecondPOC
Dim newPoc As New Alveare_VB.Alv_Product_Order_Control
AddHandler newPoc.CreateNew, AddressOf CreateSecondPOC
FlowLayoutPanel1.Controls.Add(newPoc)
End Sub
But the last POC control's event handler would never be unsubscribed. So you could also do something like this when closing the form
For Each poc In Me.FlowLayoutPanel1.Controls.OfType(Of Alveare_VB.Alv_Product_Order_Control)()
RemoveHandler poc.CreateNew, AddressOf CreateSecondPOC
Next poc
I mentioned above that You could also keep all your POC controls in a container, which would be a better way to keep track of your controls, instead of using the FlowLayoutPanel as logical container. Just do what works for you and consider removing the handlers.
In Form4 i have a DataGridView named DbTableDataGridView.
In Form3 there is a set of fields (text boxes) that are all bound to the DbTableBindingSource . When I run application the Form4 shows up. There is a button to open new form (Form3) and in there enter details about customers to be added as new row into database (DataGridView). My code for the "Add" button in Form4 looks like this:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.DbTableDataGridView.Refresh()
Me.DbTableBindingSource.AddNew()
Form3.ShowDialog()
Form3.ImiéTextBox.Text = ""
Form3.NazwiskoTextBox.Text = ""
Form3.Numer_TelefonuTextBox.Text = ""
Form3.Numer_RejestracyjnyTextBox.Text = ""
Form3.MarkaTextBox.Text = ""
Form3.ModelTextBox.Text = ""
Form3.Poj_SilnikaTextBox.Text = ""
Form3.RocznikTextBox.Text = ""
Form3.PaliwoTextBox.Text = ""
Form3.Data_PrzyjeciaDateTimePicker.Value = DateTime.Now
Form3.RichTextBox1.Text = ""
End Sub
It does add new row, selects it and clears entries in the text boxes (that are bound into 'DbTableBindingSource'.
In this form after I fill in all the fields I press button save:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
Me.Validate()
Form4.DbTableBindingSource.EndEdit()
Me.DbTableTableAdapter.Update(CartronicDBDataSet.dbTable)
TableAdapterManager.UpdateAll(CartronicDBDataSet)
DbTableTableAdapter.Fill(Form4.CartronicDBDataSet.dbTable)
MsgBox("Saved")
Catch ex As Exception
MessageBox.Show("Blad zapisu. Sprobuj ponownie. W razie potrzeby zamknij, a nastepnie uruchom ponownie program Cartronic")
End Try
End Sub
It goes to the message "Saved" but actually does not fill in added new recently.
Any thoughts?
There is no link that I can see between Form3 and your data.
I'd recommend passing the newly created data row to a new instance of Form3.
Get the reference to your newly added row
Create a new Form3 (avoid default instance forms, they're ugly and evil). This will mean you don't need to clear the textboxes as you have a brand new form every time.
Pass the datarow into your form where you will bind it directly to the textboxes
Dim newRow = CType(Me.DbTableBindingSource.AddNew(), DataRow)
Using frmEditor As New Form3
frmEditor.DataSource = newRow
frmEditor.ShowDialog()
End Using
In form3 add the property (or preferably a constructor)
Private mDataSource As DataRow
Public Property DataSource As DataRow
Get
Return mDataSource
End Get
Set(value As DataRow)
mDataSource = value
Me.ImiéTextBox.DataBindings.Add("Text", mDataSource, "ImiéFieldName")
' ....
End Set
End Property
If you use this approach then you can get rid of all of the textbox clearing code.
I have done what you have suggested but little bit simpler.
Assigned all text boxes to each cell in current row as follows:
Form4.DbTableDataGridView.CurrentRow.Cells(5).Value = Me.NazwiskoTextBox.Text.ToString
Form4.DbTableDataGridView.CurrentRow.Cells(4).Value = Me.ImiéTextBox.Text.ToString
It works fine.
Cheers
I have a datagridview named datagridview1 inculude a table from ms sql. I want to select a cell and then select another without unselecting the first cell that I have selected before. How can I do that?
I tried this code which is not selecting anything:
Private Sub DataGridView1_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellClick
If DataGridView1.CurrentCell.Selected = True Then
DataGridView1.CurrentCell.Selected = False
Else
DataGridView1.CurrentCell.Selected = True
End If
End Sub
Any suggestions?
I guess then that you could roll your own datagridview and override the OnCellMouseDown and OnCellMouseUp events to give you this effect without the mouseup cancelling out the currently selected items.
Create a new class in your solution and inherit the datagridview
Public Class MyDataGridView
Inherits DataGridView
Protected Overrides Sub OnCellMouseDown(e As DataGridViewCellMouseEventArgs)
Me.Rows(e.RowIndex).Cells(e.ColumnIndex).Selected = Not Me.Rows(e.RowIndex).Cells(e.ColumnIndex).Selected
End Sub
Protected Overrides Sub OnCellMouseUp(e As DataGridViewCellMouseEventArgs)
End Sub
End Class
This should cancel out the what happens when the mouseclick event process fully which in a standard cell, will deselect the previous selection (unless the CTRL key is used).
Add this code, compile it and you should see at the top of your toolbox a MyDataGridView control. Drag it onto your form, populate it and give it a go.
Good day everyone.
I need your help in this project I am into (a Visual Basic program with no database.) It just contains a Datagridview, a Textbox, and three buttons (an "Add" Button, a "Edit" and an "Update" Button).
1 . Is there any way (like using "for loop") to automatically assign DataGridView1.Item("item location") to the one edited and be updated?
2 . Or is it possible to just click an item in the Datagridview then it will be edited at that without passing it to a Textbox, and to be updated at that.
The DataGridViewCellEventArgs variable (e in the method stub the designer will generate for you) of the double click event of the cell has RowIndex and ColumnIndex properties which refer to the position of the cell you clicked.
Save those (in a class variable possibly or a local one if that's all you need) and then refer to them when you update the cell in your DataGridView, possibly like this MyDataGridView.Item(e.ColumnIndex, e.RowIndex) or MyDataGridView.Rows(e.RowIndex).Cells(e.ColumnIndex) where e is the variable from the double click event handler.
For you cell double click event you could have something like this:
Private Sub DataGridView1_CellDoubleClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellDoubleClick
Using myEditor As New frmCellEditor(Me.DataGridView1.Item(e.ColumnIndex, e.RowIndex).Value)
If myEditor.ShowDialog() = DialogResult.OK Then
Me.DataGridView1.Item(e.ColumnIndex, e.RowIndex).Value = myEditor.NewCellValue
End If
End Using
End Sub
This will call a new instance of your editor and get a value from you. For the purpose of this demo I have made a form like this:
Public Class frmCellEditor
Public NewCellValue As Integer
Public Sub New(ByVal CurrentCellValue As Object)
InitializeComponent()
Me.TextBox1.Text = CStr(CurrentCellValue)
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.NewCellValue = CInt(Me.TextBox1.Text)
Me.DialogResult = DialogResult.OK
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Call Me.Close()
End Sub
End Class
Which just has two buttons (Button1 = OK, Button2 = Cancel). When you click OK, it just returns the value 1 which then gets set as the value of the cell.
This is a VERY simplistic example, but it should provide you the basics of what you are trying to do.
UPDATE:
I updated the code for the editor interface so it will include handling for passing the value back and forth from the form with your datagridview.
In your project, make a new form called frmCellEditor. This forms has to have two buttons and a textbox (Make sure that the programmatic names match!). Replace the code with the code listed above. You will have to add Imports System.Windows.Forms above the class as well.
Amend the event handler for the cell double click event of your datagrid to pass the cell value when frmCellEditor is constructed (the line going ... New frmCellEditor(...).
How many columns does your DataGridView has?
Based on how you populate your DataGridView, I'll assume only 1.
Declare this on top of your form
Dim i as Integer
On your btnUpdate_Click Event (Just combine your Edit and Update button into One)
SELECT CASE btnUpdate.Text
Case "Update"
With DataGridView1
'Check if there is a selected row
If .SelectedRows.Count = 0 Then
Msgbox "No Row Selected for Update"
Exit Sub
End If
i = .CurrentRow.Index 'Remember the Row Position
Textbox1.Text = .item(0 ,i).value 'Pass the Value to the textbox
.Enabled = False 'Disable DataGridView to prevent users from clicking other row while updating.
btnUpdate.Text = "Save"
End With
Case Else 'Save
DatagridView1.Item(0,i).Value = Textbox1.Text
btnUpdate.Text = "Update"
END SELECT
Thanks for those who contributed to finding answers for this thread. I have not used your solutions for now (maybe some other time). After some research, I've found an answer for problem 2 (more user friendly at that):
2 . Or is it possible to just click an item in the Datagridview then
it will be edited at that without passing it to a Textbox, and to be
updated at that.
Here's what i did:
in Private Sub Form1_Load, just add:
yourDataGridView.EditMode = DataGridViewEditMode.EditOnEnter
in Private Sub yourDataGridView_(whatever event here: DoubleCellClick, CellContentClick, etc.) add:
DataGridView1(e.ColumnIndex, e.RowIndex).[ReadOnly] = False
DataGridView1.BeginEdit(False)