I already check this question - prevent listview to lose selected item .
but I need this code for VB.Net. I already used c# to vb converter and the output is this.
Private Sub ListView_SelectionChanged(sender As Object, e As SelectionChangedEventArgs)
Dim listView As ListView = TryCast(sender, ListView)
If listView.SelectedItems.Count = 0 Then
For Each item As Object In e.RemovedItems
listView.SelectedItems.Add(item)
Next
End If
End Sub
And the error is : 'SelectionChangedEventArgs' is not defined.
I replaced the SelectionChangedEventArgs to ByVal e As System.EventArgs
and now the error is:
'RemovedItems' is not a member of 'System.EventArgs'.
Property: HideSelection = False also not working for me.
How will I able to maintain the row selected?
Related
I am here to find out is it possible to complete my idea to save me time writing long code.
I have 1 main combobox with various items and some other comboboxed. Each combobox of them is called "Combo" + the item from the main combobox.
and I wonder can I, when I click on an item to hide the last used combobox and to show the combobox linked to this item?
1. hide last used combobox
2. show the combobox responding to the selected item from the main combox
Public Sub ComboBox2_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox2.SelectedIndexChanged
Dim SelectedAction As String = "Combo" + ComboBox2.Text
lastcombobox.visible = false
' now to assign to the new combobox
lastcombobox = (SelectedAction as name of combobox) combobox
Lastcombobox.visible = true
End Sub
Strings are not controls. Strings are the data type of Control.Name; that is the Name property of the control object. You cannot cast a string to a control but all is not lost. Create your other Combo Boxes at design time and stack them on top of each other. Notice the Static keyword before lastComboBox. This persists the value between calls to the method. You could accomplish the same thing by making this variable a class level variable. The first time the method is called their will be nothing in lastComboBox therefore the check for IsNothhing. Control.Find returns an array so we must refer to ctl(0) - the first element of the array, since we know it will return only one.
Private Sub Combo2_SelectedIndexChanged(sender As Object, e As EventArgs) Handles Combo2.SelectedIndexChanged
Dim SelectedAction As String = "Combo" & Combo2.Text
Static lastComboBox As ComboBox
If Not IsNothing(lastComboBox) Then
lastComboBox.Visible = False
End If
Dim ctl() As Control = Controls.Find(SelectedAction, True)
lastComboBox = CType(ctl(0), ComboBox)
lastComboBox.BringToFront()
lastComboBox.Visible = True
End Sub
I've come across a rather strange behavior.
Behind my form i have my constructor which looks like this:
Private Property SourceDatatable As DataTable
Public Sub New()
' This call is required by the designer.
InitializeComponent()
SourceDatatable = GetData()
'SourceDatatable now has 500 rows
AvailableObjects.DataSource = SourceDatatable
End Sub
Right now all 500 rows are visible inside the gridview.
When the user clicks a button, then the selected row is 'copied'
Private Sub CopyObject_Click(sender As System.Object, e As System.EventArgs) Handles AddNewObject.Click
Dim selectedRow As Integer = GridviewAvailableObjects.GetSelectedRows().FirstOrDefault()
If (selectedRow > 0) Then
Dim selectedDataRow As Integer = GridviewAvailableObjects.GetRowHandle(selectedRow)
SelectedRecords.Rows.Add(SourceDatatable.Rows(selectedDataRow))
End If
GridViewSelectedValues.RefreshData()
End Sub
The error occurs at SourceDatatable.Rows(selectedDataRow). All of a sudden it has 0 rows, Yet selectedDataRow refers to the correct row in the datasource(datatable). There is no interference of other Methods/Code as these 2 methods are the only ones present on the form and there is no other code on this form. Nor is the grid or any control accessible from outside the form.
What could cause this strange behavior? Does de Devexpress Gridview do anything with the datasource?
You should not directly add rows from one table to another due to DataTable restrictions - it will throw the System.ArgumentException ("This row already belongs to another table") exception. This issue is not specific to DevExpress GridView. And you can avoid it with easy via copying only "values" from the original row into another table.
This version of "copying" works to me, please review it:
void btnCopy_Click(object sender, EventArgs e) {
var selectedRowHandles = gridViewForAllData.GetSelectedRows();
for(int i = 0; i < selectedRowHandles.Length; i++) {
var selectedRow = gridViewForAllData.GetDataRow(selectedRowHandles[i]);
selectedRowsTable.Rows.Add(selectedRow.ItemArray);
}
gridViewForSelectedValues.RefreshData();
}
VB.Net:
Private Sub btnCopy_Click(ByVal sender As Object, ByVal e As EventArgs) Handles simpleButton1.Click
Dim selectedRowHandles = gridViewForAllData.GetSelectedRows()
For i As Integer = 0 To selectedRowHandles.Length - 1
Dim selectedRow = gridViewForAllData.GetDataRow(selectedRowHandles(i))
selectedRowsTable.Rows.Add(selectedRow.ItemArray)
Next i
gridViewForSelectedValues.RefreshData()
End Sub
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)
In VB6 there is a feature called Control Arrays, where you name controls the same name and provide them an index value. This allows you to set a value by looping through the controls and setting each value. In VB .NET I can't create a control array could someone provide me with a similar solution.
Here is a sample I wrote for something else that shows how to do something similar and shows how to do the handler as well. This makes a 10x10 grid of buttons that turn red when you click them.
Dim IsCreated(99) As Boolean
Dim Buttons As New Dictionary(Of String, Button)
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
For i As Integer = 0 To 99
Dim B As New Button
Me.Controls.Add(B)
B.Height = 30
B.Width = 40
B.Left = (i Mod 10) * 41
B.Top = (i \ 10) * 31
B.Text = Chr((i \ 10) + Asc("A")) & i Mod 10 + 1
Buttons.Add(B.Text, B)
B.Tag = i
AddHandler B.Click, AddressOf Button_Click
Next
End Sub
Private Sub Button_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Dim B As Button = sender
IsCreated(B.Tag) = True
B.BackColor = Color.Red
End Sub
Avoid using the proposed iteration approaches, you'll get a fairly random collection of controls unless your form is very simple. Simply declare the control array in your code and initialize it in the form constructor. Like this:
Public Class Form1
Private OrderNumbers() As TextBox
Public Sub New()
InitializeComponent()
OrderNumbers = New TextBox() {TextBox1, TextBox2}
End Sub
End Class
You can now treat OrderNumbers just like you could in VB6.
Maybe this is simpler. To create a control array, I put the control array declaration in a module. For example, if I have a Form with three TextBoxes and I want the TextBoxes to be part of a control array called 'mytext', I declare my control array in a module as follows:
Module Module1
Public mytext() As TextBox = {Form1.TextBox1, Form1.TextBox2, Form1.TextBox3}
End Module
And, I use the TextBoxes from the control array as follows:
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
mytext(0).Text = "Hello"
mytext(1).Text = "Hi"
mytext(2).Text = "There"
End Sub
End Class
You can even loop through the control array, like you could in VB6:
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
For i As Integer = 0 To 2
mytext(i).Text = i + 1
Next
End Sub
End Class
The beauty of using a module is that the TextBoxes do not even need to be in the same form.
With Winforms, you could do this:
myForm.Controls _
.OfType(Of TextBox) _
.OrderBy(Function(c) c.Name) _
.Where(Function(c) c.Name.StartsWith("somePrefix")) _
.ToArray()
On your form you would name your textboxes somePrefix1, somePrefix2, etc.
Here is an old article but it could give you more information. The top method is super easy.
Your Form, or PanelControl, or anything else that can contain child controls will have a Property called Controls.
You can loop through all of the text boxes in a control by using
'Create a List of TextBoxes, like an Array but better
Dim myTextBoxControls As New List
For Each uxControl As UserControl in MyFormName.Controls
If TypeOf(uControl) is TextBox
myTextBoxControls.Add(uControl)
End IF
Next
Now you have your iterate-able collection you can work with.
You can access a TextBoxes value with the EditValue property.
After looking at what you're trying to do a little further.
You probably want to name all of your controls with a Prefix, let's say abc for now.
For Each uxControl As UserControl in MyFormName.Controls
If TypeOf(uControl) is TextBox Then
Dim tbControl As TextBox = DirectCast(uControl, TextBox)
If tbControl.Name.StartsWith("abc") Then
tbControl.EditValue = "the Value you want to initialize"
End If
End If
Next
So this is one of the features that did not make the transition to VB.NET -- exactly :-( However, you can accomplish much of what you would have done in VB6 with two different mechanisms in .NET: Looping through the controls collection and handling control events.
Looping Through the Controls Collection
In VB.NET every form and control container has a controls collection. This is a collection that you can loop through and then do an operation on the control like set the value.
Dim myTxt As TextBox
For Each ctl As Control In Me.Controls
If TypeOf ctl Is TextBox Then
myTxt = CType(ctl, TextBox)
myTxt.Text = "something"
End If
Next
In this code sample you iterate over the controls collection testing the type of the returned object. If you find a textbox, cast it to a textbox and then do something with it.
Handling Control Events
You can also handle events over multiple controls with one event handler like you would have using the control array in VB6. To do this you will use the Handles keyword.
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged
Dim myTxt As TextBox = CType(sender, TextBox)
MessageBox.Show(myTxt.Text)
End Sub
The key here is the Handles keyword on the end of the event handler. You separate out the various controls that you want to handle and the event by using a comma. Make sure that you are handling controls that have the same event declaration. If you ever wondered what sender was for on every event well here's one of the uses for it. Cast the sender argument to the type of control that you are working with and assign it to a local variable. You will then be able to access and manipulate the control that fired the event just like you would have in VB6 if you specified and index to the array.
Using these two techniques you can replicate the functionality of control arrays in VB6. Good luck.
Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
Dim a() As Control = GetControls("textbox")
For Each c As TextBox In a
c.Text = c.Name
Next
End Sub
Private Function GetControls(typeOfControl As String) As Control()
Dim allControls As New List(Of Control)
'this loop will get all the controls on the form
'no matter what the level of container nesting
'thanks to jmcilhinney at vbforums
Dim ctl As Control = Me.GetNextControl(Me, True)
Do Until ctl Is Nothing
allControls.Add(ctl)
ctl = Me.GetNextControl(ctl, True)
Loop
'now return the controls you want
Return allControls.OrderBy(Function(c) c.Name). _
Where( _
Function(c) (c.GetType.ToString.ToLower.Contains(typeOfControl.ToLower) AndAlso _
c.Name.Contains("Box")) _
).ToArray()
End Function
I'm migrating an application from VB6 to VB.Net and I found a change in the behavior of the ListBox and I'm not sure of how to make it equal to VB6.
The problem is this:
In the VB6 app, when the ListBox is focused and I type into it, the list selects the element that matches what I type. e.g. If the list contains a list of countries and I type "ita", "Italy" will be selected in the listbox.
The problem is that with the .Net version of the control if I type "ita" it will select the first element that starts with i, then the first element that starts with "t" and finally the first element that starts with "a".
So, any idea on how to get the original behavior? (I'm thinking in some property that I'm not seeing by some reason or something like that)
I really don't want to write an event handler for this (which btw, wouldn't be trivial).
Thanks a lot!
I shared willw's frustration. This is what I came up with. Add a class called ListBoxTypeAhead to your project and include this code. Then use this class as a control on your form. It traps keyboard input and moves the selected item they way the old VB6 listbox did. You can take out the timer if you wish. It mimics the behavior of keyboard input in Windows explorer.
Public Class ListBoxTypeAhead
Inherits ListBox
Dim Buffer As String
Dim WithEvents Timer1 As New Timer
Private Sub ListBoxTypeAhead_KeyDown(sender As Object, _
e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
Select Case e.KeyCode
Case Keys.A To Keys.Z, Keys.NumPad0 To Keys.NumPad9
e.SuppressKeyPress = True
Buffer &= Chr(e.KeyValue)
Me.SelectedIndex = Me.FindString(Buffer)
Timer1.Start()
Case Else
Timer1.Stop()
Buffer = ""
End Select
End Sub
Private Sub ListBoxTypeAhead_LostFocus(ByVal sender As Object, _
ByVal e As System.EventArgs) Handles Me.LostFocus
Timer1.Stop()
Buffer = ""
End Sub
Public Sub New()
Timer1.Interval = 2000
End Sub
Private Sub Timer1_Tick(sender As Object, e As System.EventArgs) Handles Timer1.Tick
Timer1.Stop()
Buffer = ""
End Sub
End Class
As you probably know, this feature is called 'type ahead,' and it's not built into the Winform ListBox (so you're not missing a property).
You can get the type-ahead functionality on the ListView control if you set its View property to List.
Public Function CheckIfExistInCombo(ByVal objCombo As Object, ByVal TextToFind As String) As Boolean
Dim NumOfItems As Object 'The Number Of Items In ComboBox
Dim IndexNum As Integer 'Index
NumOfItems = objCombo.ListCount
For IndexNum = 0 To NumOfItems - 1
If objCombo.List(IndexNum) = TextToFind Then
CheckIfExistInCombo = True
Exit Function
End If
Next IndexNum
CheckIfExistInCombo = False
End Function