I am a self learning student in VB.Net. I have created a user control with TabControl.
I have added it dynamically to a new TabControl while add button is clicked. But I don't know how to modify the content of the control in the user control. Kindly help me in accessing the control inside user control in a tabcontrol.
Public Class Form1
Dim n As Integer
Dim a As string
Dim b As Object
Private Sub btnAddTabPage_Click(sender As Object, e As EventArgs) Handles btnAddTabPage.Click
Dim tabpage As New TabPage
tabpage.Text = "USERPanel-" + n.ToString
tabpage.Name = "USERTab-" + n.ToString
tcUsers.TabPages.Add(tabpage)
tcUsers.SelectedTab = tabpage
n = n + 1
'Dim lbltabname As Label = New Label
'lbltabname.Text = tpUsers.SelectedTab.Name.ToString
'tpUsers.SelectedTab.Controls.Add(lbltabname)
Dim ctrl As Userdata = New Userdata
ctrl.Name = "USERdata-" + n.ToString
tcUsers.SelectedTab.Controls.Add(ctrl)
ctrl.lblUserName.Text = tcUsers.SelectedTab.Name.ToString
ctrl.lblUserAge.Text = tcUsers.SelectedTab.Text.ToString
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
n = 1
End Sub
Private Sub btnDeleteTabPage_Click(sender As Object, e As EventArgs) Handles btnDeleteTabPage.Click
tcUsers.TabPages.Remove(tcUsers.SelectedTab)
End Sub
End Class
For Eg.
I have a textbox in the user control. I need to modify the content of the text box.
Related
I need to add some controls to a Visual Basic 2017 form programmatically. One of the controls is a textbox that needs a changetext event handler. Below is some code that accomplishes that task.
HOWEVER, the changetext event handler seems to fire right away, before the form even loads... before the textbox itself even loads! A "click" handler works fine, as expected. But changetext? Nope.
I've thrown together a simplified version to demonstrate. The line with the "DIES RIGHT HERE" comment causes the problem (not the comment, but the code to the left of it).
A textbox that is added at design time will work fine, not cause this problem, but that isn't an option.
What's causing this the changetext handler to be run early? How do I work around this?
Public Class Form1
Dim txtTest As TextBox
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim pntTextBox As Point
pntTextBox.X = 100
pntTextBox.Y = 100
txtTest = New TextBox
With txtTest
.Location = pntTextBox
.Width = 100
AddHandler txtTest.TextChanged, AddressOf txtTest_TextChanged
End With
Me.Controls.Add(txtTest)
End Sub
Private Sub txtTest_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyClass.TextChanged
Dim strTest As String
strTest = Str(txtTest.Width) ' ****** DIES RIGHT HERE
MsgBox(strTest)
End Sub
End Class
Made a few changes. Works.
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
For x As Integer = 1 To 2 'create multiple TB's
Dim pntTextBox As Point
pntTextBox.X = 100 * x
pntTextBox.Y = 100
Dim txtTest As TextBox = New TextBox
With txtTest
txtTest.Name = "tb_" & x.ToString
AddHandler txtTest.TextChanged, AddressOf txtTest_TextChanged
.Location = pntTextBox
.Width = 100
End With
Me.Controls.Add(txtTest)
Next
End Sub
Private Sub txtTest_TextChanged(ByVal sender As Object,
ByVal e As System.EventArgs) 'no handler at design time
Dim tb As TextBox = DirectCast(sender, TextBox)
Dim strTest As String
strTest = tb.TextLength.ToString
Debug.WriteLine("{0} {1}", tb.Name, strTest) 'put breakpoint here
End Sub
End Class
My program contains buttons in a FlowLayoutPanel.
I want to disable any button when right click on it and click "Disable" in the ContextMenuStrip.
My code is:
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
For i As Integer = 0 To 30
Dim btn As New Button
btn.Name = i
btn.Text = i
btn.ContextMenuStrip = ContextMenuStrip1
FlowLayoutPanel1.Controls.Add(btn)
Next
End Sub
End Class
declare a public varibale for keeping a control
public ctrl as button = nothing
you can create a right click by putting this code on mouse down...
If e.Button <> Windows.Forms.MouseButtons.Right Then Return
Dim cms = New ContextMenuStrip
ctrl = sender
Dim item1 = cms.Items.Add("Disable")
item1.Tag = 1
AddHandler item1.Click, AddressOf Disable
end if
and in the diable sub you can code like this...
Private Sub Disable()
ctrl.enabled = false
End Sub
I'm working on a program wherein I have around 400 Text Boxes and I need to program an effect to make them show that they have focus. I can get the visual part down (Unless someone knows how to add a soft blue outline to a text box in VB), but I'm having trouble with creating GotFocus and LostFocus events that handle all of my Text Boxes at once. I've tried
Dim txtBox = Me.Controls.OfType(Of TextBox)
Private Sub TextBox_GotFocus(sender As Object, e As EventArgs) Handles txtBox.GotFocus
But I get a "Must have WithEvents variable" error which I don't quite understand how to fix. I've tried
Public Sub txtBoxGotFocusHandler(ByVal sender As Object,
ByVal e As System.EventArgs)
For Each txtBox As TextBox In Me.Controls 'References all text boxes in form
If txtBox.Focus = True Then
txtBox.BackColor = Color.Black
End If
Next
And I've tried a few other somewhat related things I've seen around the internet, but to no avail. Any help would be appreciated
You can make your app at runtime with any controls. You could query the layout of your app from SQL and from a simple change your app layout changes.
Private FocusRectangle As System.Drawing.Graphics
Private OldRectangle As System.Drawing.Graphics
Private MyTextBoxes As New List(Of TextBox)
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
MyTextBoxes.Clear()
For xcount = 0 To 399
MyTextBoxes.Add(New TextBox)
With MyTextBoxes.Item(xcount)
.Name = "MyTextBoxes" & (xcount + 1).ToString
.Text = ""
.Location = New Point(0, 0)
.Size = New Size(50, 13)
.Visible = True
AddHandler .GotFocus, AddressOf MyTextBoxes_GotFocus
AddHandler .LostFocus, AddressOf MyTextBoxes_LostFocus
End With
Me.Controls.Add(MyTextBoxes.Item(xcount))
'add them to a panel....
'Panel1.Controls.add(MyTextBoxes.Item(xcount))
Next
End Sub
Sub MyTextBoxes_GotFocus(sender As Object, e As EventArgs)
Dim ThisTextBox As TextBox = DirectCast(sender, TextBox)
Dim xPen As New System.Drawing.Pen(Color.LightBlue)
FocusRectangle = Me.CreateGraphics()
FocusRectangle.DrawRectangle(xPen, ThisTextBox.Location.X - 1, ThisTextBox.Location.Y - 1, ThisTextBox.Size.Width + 1, ThisTextBox.Size.Height + 1)
OldRectangle = FocusRectangle
End Sub
Sub MyTextBoxes_LostFocus(sender As Object, e As EventArgs)
Dim ThisTextBox As TextBox = DirectCast(sender, TextBox)
OldRectangle.Dispose()
End Sub
Private Sub Form1_MouseMove(sender As Object, e As MouseEventArgs) Handles Me.MouseMove
MyTextBoxes.Item(0).Focus()
End Sub
If you created your form with the Designer, the WithEvents is added for you automatically.
If you are declaring 400 text boxes as Private fields, you would declare them as Private WitheEvents txtBox As TextBox
If you're creating the text boxes programatically and adding them to a collection of textboxes or something, then you can't do WithEvents.
But all WithEvents does is allow you to add Handeles TextBox.SomeEvent to a function. Instead you can do this:
Dim txtBox As New TextBox
...
AddHandler txtBox.GotFocus, AddressOf txtBoxGotFocusHandler
Me.Controls.Add(txtBox)
i am attaching a single context menu to multiple text box. so, i need to get the control name/reference that used to show the context menu.
below is the sample image of my context menu:
Below is the code for green marked "paste" item click event:
Dim objTSMI As ToolStripMenuItem
Dim objCMS As ContextMenuStrip
Dim objTxtBox As System.Windows.Forms.TextBox
objTSMI = CType(sender, ToolStripMenuItem)
objCMS = CType(objTSMI.Owner, ContextMenuStrip)
objTxtBox = CType(objCMS.SourceControl, System.Windows.Forms.TextBox)
If Clipboard.ContainsText(TextDataFormat.Text) = True Then
objTxtBox.SelectedText = Clipboard.GetText(TextDataFormat.Text)
End If
it works very fine.
but below is my code for red marked "Page count" item click event:
Dim objTSMI As ToolStripMenuItem
Dim objCMS As ContextMenuStrip
Dim objTxtBox As System.Windows.Forms.TextBox
objTSMI = CType(sender, ToolStripMenuItem)
objCMS = CType(objTSMI.Owner, ContextMenuStrip)
objTxtBox = CType(objCMS.SourceControl, System.Windows.Forms.TextBox)
MessageBox.Show(objTxtBox.Name)
but above throws following error :
Unable to cast object of type 'System.Windows.Forms.ToolStripDropDownMenu' to type 'System.Windows.Forms.ContextMenuStrip'.
here is the screenshot of the error:
so, i can't figure it out what is the issue.
any help would be highly appreciated
If you check this C# thread the accepted answer notes it is a bug. The workaround presented there uses a private variable to store the SourceControl on the Opening event of the ContextMenuStrip. I've converted to VB.NET and used the Tag of the ContextMenuStrip instead of using the variable. You then refer to the Tag property instead of the faulty SourceControl property:
Imports System.ComponentModel
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.TextBox1.ContextMenuStrip = Me.ContextMenuStrip1
Me.TextBox2.ContextMenuStrip = Me.ContextMenuStrip1
End Sub
Private Sub ContextMenuStrip1_Opening(sender As Object, e As CancelEventArgs) Handles ContextMenuStrip1.Opening
Me.ContextMenuStrip1.Tag = CType(Me.ContextMenuStrip1.SourceControl, Control)
End Sub
Private Sub TestToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles TestToolStripMenuItem.Click
' first level of context menu strip
Dim Strip As ContextMenuStrip = CType(sender, ToolStripMenuItem).Owner
Dim Box As TextBox = Strip.Tag
MessageBox.Show(Box.Name)
End Sub
Private Sub ChildToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ChildToolStripMenuItem.Click
' second level of context menu strip
Dim Strip As ContextMenuStrip = CType(sender, ToolStripMenuItem).OwnerItem.Owner
Dim Box As TextBox = Strip.Tag
MessageBox.Show(Box.Name)
End Sub
End Class
Dim ControlsName as string
Private Sub ContextMenuStrip1_Opening(sender As Object, e As System.ComponentModel.CancelEventArgs) Handles ContextMenuStrip1.Opening
ControlsName= ContextMenuStrip1.SourceControl.Name.ToString
End Sub
How do I make a control array for buttons in VB.NET? Like in Visual Basic 6.0...
Is it possible that the syntax can be like the following?
dim a as button
for each a as button in myForm
a.text = "hello"
next
Controls in .NET are just normal objects so you can freely put them into normal arrays or lists. The special VB6 construct of control arrays is no longer necessary.
So you can for example say,
Dim buttons As Button() = { Button1, Button2, … }
For Each button As Button In Buttons
button.Text = "foo"
End For
Alternatively, you can directly iterate over the controls inside a container (e.g. a form):
For Each c As Control In MyForm.Controls
Dim btt As Button = TryCast(c, Button)
If btt IsNot Nothing Then ' We got a button!
btt.Text = "foo"
End If
End For
Notice that this only works for controls that are directly on the form; controls nested into containers will not be iterated this way; you can however use a recursive function to iterate over all controls.
You can't create a control array in VB.NET, but you can archive similar functionality using the Handles keyword.
public sub Button_Click(sender as Object, e as EventArgs) Handles Button1.Click, Button2.Click, Button3.Click
'Do Something
End Sub
Yes, you can do this. But I don't think you can iterate buttons directly by giving myForm.
You create a Form and add a Layout 10 * 10, and try this,
Public Class Form1
Private NRow As Integer = 10
Private NCol As Integer = 10
Private BtnArray(NRow * NCol - 1) As Button
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
TableLayoutPanel1.Size = Me.ClientSize
For i As Integer = 0 To BtnArray.Length - 1
BtnArray(i) = New Button()
BtnArray(i).Anchor = AnchorStyles.Top Or AnchorStyles.Bottom Or AnchorStyles.Left Or AnchorStyles.Right
BtnArray(i).Text = CStr(i)
TableLayoutPanel1.Controls.Add(BtnArray(i), i Mod NCol, i \ NCol)
AddHandler BtnArray(i).Click, AddressOf ClickHandler
Next
End Sub
Public Sub ClickHandler(ByVal sender As Object, ByVal e As System.EventArgs)
MsgBox("I am button #" & CType(sender, Button).Text)
End Sub
End Class