I have a series of controls: TextBox, Label and Panel. There controls are created dynamically in the code not the designer. My problem is that How can I call The Label and The Panel control using the .Name property that I set in the code?
This is what I have
Public Class frmMain
Private Sub DraControls()
Dim pans as New Panel
With pans
.AutoSize = True
.Parent = Me
.Name = "Panel1"
End With
Dim labs as New Label
With labs
.Text = "%"
.Name = "PercentageLabel00"
.Parent = pans
End With
End Sub
End Class
Then I have a click event that will make the label change its Text.
Dim PercentTextLabel As Label = CType(Me.Controls("PercentageLabel00"), Label)
PercentTextLabel.Text = "OK"
I need to change the text of the Label and I am getting an Error System.NullReferenceException: 'Object reference not set to an instance of an object.'
I already treid other approaches like Controls.Find but I got the same results
Thanks!
As per comments.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim p As Panel = CType(Me.Controls("Panel1"), Panel)
CType(p.Controls("PercentageLabel00"), Label).Text = "OK"
End Sub
Or in a single line
CType(CType(Me.Controls("Panel1"), Panel).Controls("PercentageLabel00"), Label).Text = "OK"
Related
So here's what I have:
Code that makes buttons when you click the button "New Button" (Button1).
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
ActionsMade = ActionsMade + 1
Dim actionButton = New Windows.Forms.Button
ActionContainer.Controls.Add(actionButton)
actionButton.Text = "New Action " + ActionsMade.ToString
actionButton.Width = 107
actionButton.Height = 56
AddHandler actionButton.Click, AddressOf OnActionButtonClick
End Sub
When you click the buttons that were created, it shows an input box, where you type what you want to rename the button to.
Sub OnActionButtonClick()
If IsRenaming Then
Dim renameTo As String
renameTo = InputBox("Rename ActionButton To:")
Else
MessageBox.Show("Action started! Not renaming")
End If
End Sub
The only problem is, I have no way to identify between these buttons.
tl;dr:
I created buttons programmatically
I want to rename them
I don't know how to identify between these buttons and rename them individually
This is more concise and includes a referencable button name (eg Button_03):
Private Sub MakeButton_Click(sender As Object, e As EventArgs) Handles MakeButton.Click
Static ActionsMade As Integer = 0
ActionsMade += 1
ActionContainer.Controls.Add(New Button With {
.Name = $"Button_{ActionsMade:00}",
.Text = $"New Action {ActionsMade:00}",
.Size = New Size(107, 56),
.Location = New Point(100, 250 + 25 * ActionsMade)
})
AddHandler ActionContainer.Controls($"Button_{ActionsMade:00}").Click, AddressOf OnActionButtonClick
End Sub
Note that in the above code I haven't actually defined a new button per se, just New-ed it within the Controls.Add() statement, and then used the generated button name to add the event handler.
Another way would be declare the button as an independent object and then add it:
Dim actionButton As New Button With {
.Name = $"Button_{ActionsMade:00}",
.Text = $"New Action {ActionsMade:00}",
.Size = New Size(107, 56),
.Location = New Point(100, 250 + 25 * ActionsMade)
}
ActionContainer.Controls.Add(actionButton)
AddHandler actionButton.Click, AddressOf OnActionButtonClick
Other notes:
Use of a Static ActionsMade integer variable which retains its value between calls. This could also be a module-wide variable and removed from the MakeButton_Click Sub.
Use of string interpolation in assigning the button's Name and Text properties according to a formated version of the ActionsMade value.
Use of button properties Size and Location.
Automatic increment of button vertical position based on the value of ActionsMade.
Regarding your Action Button event handler, it should look like this:
Private Sub OnActionButtonClick(sender As Object, e As EventArgs)
If ActionStarted Then
MessageBox.Show("Action started! Not renaming.")
Else
CType(sender, Button).Text = InputBox("Rename ActionButton To:")
End If
End Sub
Note that I've checked for a started Action rather than a renaming in progress but that's just an illustration of an alternative approach. Note also that you don't need to know the name of the button to change its properties.
I have a bit of code where i have a dynamically created array or buttons with staff pictures on them, as well as the staff's name. I've added one handler to handle any button click from any of the buttons. where i am stuck is, if you look at the code below, it all works fine, and if you click any of the buttons you get the "aha" test message. but i want the name of the staff clicked on (so btnArray(i).Text) to be passed to the handler for further processing. I tried adding a ByVal parameter to the handler but that caused an error. what's the correct way to do this? As i said, the code below works for me, i just am at a loss as to how to add the extra functionality.
Dim btnArray(staffcount) As System.Windows.Forms.Button
For i As Integer = 1 To staffcount - 1
btnArray(i) = New System.Windows.Forms.Button
btnArray(i).Visible = True
btnArray(i).Width = 80
btnArray(i).Height = 101
btnArray(i).BackgroundImage = Image.FromFile(picloc(i))
btnArray(i).BackgroundImageLayout = ImageLayout.Stretch
btnArray(i).Text = staffname(i)
Dim who As String
who = btnArray(i).Text
AddHandler btnArray(i).Click, AddressOf Me.theButton_Click
btnArray(i).ForeColor = Color.White
btnArray(i).TextAlign = ContentAlignment.BottomCenter
Dim fnt As Font
fnt = btnArray(i).Font
btnArray(i).Font = New Font(fnt.Name, 10, FontStyle.Bold)
FlowLayoutPanel1.Controls.Add(btnArray(i))
Next i
End Sub
Private Sub theButton_Click()
MsgBox("aha")
End Sub
First, correct the signature of your shared handler.
Private Sub theButton_Click(sender As Object, e As EventArgs)
End Sub
Once that is done getting the text of the button clicked is a simple matter.
Private Sub theButton_Click(sender As Object, e As EventArgs)
Dim textOfButtonClicked As String = DirectCast(sender, Button).Text
MessageBox.Show(textOfButtonClicked)
End Sub
The sender is the button that was clicked. Since signatures use objects for the sender the DirectCast 'changes' it to button and you then can access the .Text property of the button.
If there are more manipulations you want to perform on the clicked button you could do it this way
Private Sub theButton_Click(sender As Object, e As EventArgs)
Dim whBtn As Button = DirectCast(sender, Button) ' get reference to button clicked
Dim textOfButtonClicked As String = whBtn.Text
MessageBox.Show(textOfButtonClicked)
'e.g. change the color
whBtn.BackColor = Color.LightYellow
End Sub
Just like in excel for a graph you can double click on a title, series name, or axis label and then you are able to type in that space. What do I need to do so I can do that for my charts? Clueless on where to start. Seems I may have to create a custom label?
Use the HitTest method of the chart.
Imports System.Windows.Forms.DataVisualization.Charting
Public Class Form1
Private Sub Chart1_MouseDoubleClick(sender As Object, e As MouseEventArgs) Handles Chart1.MouseDoubleClick
Dim h As HitTestResult = Chart1.HitTest(e.X, e.Y) 'Perform the HitTest with the mouse position that was clicked
If h.ChartElementType = ChartElementType.AxisTitle OrElse _
h.ChartElementType = ChartElementType.Axis Then 'Check the type of the element of the chart that was clicked
Dim s As String = InputBox("Please enter a new title!", "", h.Axis.Title) 'Prompt for a new title
If s <> "" Then h.Axis.Title = s 'Assign the new title
End If
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
For i = 1 To 20 'Put some data in the chart to make the axes visible
Chart1.Series(0).Points.AddXY(i, i ^ 2)
Next
End Sub
End Class
You basically use the mouse location for the HitTest method. The ChartElementType defines what element was clicked at the position. If it's the title of the axis or the axis itself it will prompt you with an InputBox for a new title and assigns this title.
The InputBox is pretty old and shouldn't really be used but I was lazy and it works :-)
Apparently, what I'm referring to lives in DataVisualization.Charting.TextAnnotation. Along with that one, are many more type of annotations.
A TextAnnotation allows: AnchorMoving, Moving, PathEditing, Resizing, Selecting, and TextEditing. All of which I'm looking for.
Simple setup:
Dim anno As New DataVisualization.Charting.TextAnnotation
anno.AllowTextEditing = true
anno.AllowSelecting = true
anno.AllowMoving = true
anno.AllowResizing = true
anno.x = 50
anno.y = 50
anno.text = "Your Text"
chart.annotations.add(xAxisAnno)
I am working with a tabcontrol on which I create page one with the designer. I am creating new tab pages with controls on the pages programmatically. On each page is a several panels, each with two radiobuttons (one yes,another no). There is a panel nested inside the first panel with its visible property set to false. If the user selects yes, I want the nested panel's visible property set to true which will reveal several more radiobuttons from which they must make more choices.
My problem is in changing the nested panel's property on any page other than page one.. I can detect the radiobuttons, but I can't seem to find a way to make the nested panel visible.
Public Class ControlProgram
Dim pageindx as integer
Private Sub btnAddPrgm1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddPrgm1.Click
Dim newTab As New TabPage()
pageindx = (TabControl1.TabPages.Count + 1)
newTab.Text = "Step " & pageindx
'define fill panel controls
Dim newpnlFill As New Panel
Dim newlblFill As New Label
Dim newFillY As New RadioButton
AddHandler newFillY.CheckedChanged, AddressOf CheckforCheckedChanged
Dim newFillN As New RadioButton
AddHandler newFillN.CheckedChanged, AddressOf CheckforCheckedChanged
'add fill panel controls
With newTab.Controls
.Add(newpnlFill)
With newpnlFill
.Location = New System.Drawing.Point(6, 6)
.Size = New System.Drawing.Size(171, 137)
.BorderStyle = BorderStyle.FixedSingle
.Controls.Add(newlblFill)
With newlblFill
.Name = "Fill"
.Text = "Fill ?"
.Font = New Font(newlblFill.Font, FontStyle.Bold)
.Location = New Drawing.Point(5, 3)
End With
.Controls.Add(newFillY)
With newFillY
.Name = "FillY"
.Text = "Yes"
.Location = New Drawing.Point(23, 28)
.Size = New System.Drawing.Size(43, 17)
End With
.Controls.Add(newFillN)
With newFillN
.Name = "FillN"
.Text = "No"
.Location = New Drawing.Point(88, 28)
.Size = New System.Drawing.Size(39, 17)
End With
.Controls.Add(newpnlFill2)
With newpnlFill2
.Location = New System.Drawing.Point(2, 60)
.Size = New System.Drawing.Size(164, 68)
.BorderStyle = BorderStyle.FixedSingle
.Visible = False
End With
End With
End With
Private Sub CheckforCheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
If TypeOf sender Is RadioButton Then
bEvent = CType(sender, RadioButton).Name
End If
End Sub
End Class
I have since figured out a solution to my delima, using your suggestions as a starting point.
I added a few varribles:
Dim rb as Control
Dim bEvent as String
Dim booFillY as Boolean
Dim booFillN as Boolean
I also added the TabControl
TabControl1.TabPages.Add(newTab)
I also made these changes :
Private Sub CheckforCheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
If TypeOf sender Is RadioButton Then
rb = sender
bEvent = CType(sender, RadioButton).Name
If bEvent = "FillY" Then
Dim newpnlFill2 As Panel = rb.Parent.Controls(3)
newpnlFill2.Visible = True
End If
If bEvent = "FillN" Then
Dim newpnlFill2 As Panel = rb.Parent.Controls(3)
newpnlFill2.Visible = False
End If
End If
End Sub
Now I can make the nested panel(newpnlFill2) visible or not visible by cicking the Yes or No radiobuttons on any of the tab pages created.
thanks for your help. I doubt I would have ever gotten there on my own.
Might not be quite what you were looking for, but should be helpful get you where you need to go.
When I create an application, I like to build a list of all the controls for a given page in the load event so I can access them at any point. This is helpful because WinForms can be very picky about showing you child controls within a tabpage or groupbox, etc.
'Declare this variable within the class for your form (whatever)
Public arrControlsRecursive As New List(Of Control)
'method to recursively check all controls and build to array
Private Sub BuildControlsArrayRecursive(ByVal InControl As Control)
For Each con As Control In InControl.Controls
If con.Controls.Count > 0 Then
BuildControlsArrayRecursive(con)
End If
If TypeOf con Is Control Then
arrControlsRecursive.Add(con)
End If
Next
End Sub
'Call from MyBase.Load Event
BuildControlsArrayRecursive(Form1)
You can also just assemble a list of all tabs, for example, by changing the If statement to Is TypeOf con Is TabPage
Now you can loop through this collection or query it with LINQ. Find a single control by calling the first or single method. Cast to the type you want and do anything to any control anywhere within your form.
I don't really understand what you want to access, you first talk about
changing the nested panel's property on any page other than page one
So I assume you want to access to the other tabs, then, you talk about:
I can't seem to find a way to make the panel visible
Anyway, here's the two solutions:
Access other panels:
Private Sub CheckforCheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
If TypeOf sender Is RadioButton Then
bEvent = CType(sender, RadioButton).Name '**Where is "bEvent" declared??**
Dim newpnlFill2 as Panel = bEvent.Parent.Controls(3), Panel)
newpnlFill2.Visible = bEvent.Checked
End If
End Sub
You access to Parent that will be newpnlFill, then access to Controls(3) that it should be newpnlFill2.
Access other tabs:
Private Sub CheckforCheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs)
If TypeOf sender Is RadioButton Then
bEvent = CType(sender, RadioButton).Name '**Where is "bEvent" declared??**
Dim TabControl as TabControl = bEvent.Parent.Parent.Parent, TabControl)
'Then, you can access all of the other tabs with:
'TabControl.TabPages(n)
End If
End Sub
This assume that somewhere you add your newTab to a TabControl.
I see that you never add newTab to any TabControl, so you'll never see it..
The first Parent will be newpnlFill, the second one will reference to newTab and the last one is the TabControl that hold the Tab.
Anyway, it's something really gross, cause it assumes that your Tab is always created in this manner. For example, if you will add another panel before newpnlFill, it will not be the 4th Control in the Panel anymore, so you need to change you access code.
My advice is to create your own UserControl that inherit from TabPage, in this way you can create private variables that will always reference to the Panels you want to change. Moreover, the btnAddPrgm1_Click event will be much more clear, moving the build of the page in your class constructor.
Something like:
Private Sub btnAddPrgm1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddPrgm1.Click
Dim newTab As New MyTabPage()
pageindx = (TabControl1.TabPages.Count + 1)
newTab.Text = "Step " & pageindx
TabControl1.TabPages.Add(newTab)
End Sub
I am creating some textboxes dynamically in a custom control (actually is just a panel with a binding source that adds other sub controls at runtime.
In some of those I am setting WordWrap=True because I am expecting large text. But the textbox has only one line. Also I notice that I have to set the property AutoSize to False. When I add dynamically textboxes in a form everything is working fine (even without setting the AutoSize and the WordWrap.
Dim txt as new textbox
txt.Multiline = True
txt.AutoSize = False
txt.Size = New Size(100, 50)
txt.WordWrap = True
txt.Location = New Point(10, 10)
Me.Controls.Add(txt) 'Me is my custom Control
I checked the property WordWrap for the text box after I inserted them (with double click) and it is True.
Any ideas why I face this strange behaviour in my custom control?
Edit:
The problem is that I cannot make my text to wordwrap. So although I set MultiLine to true, AutoSize to false, WordWrap to True, the text is not changing lines. I don't want to add scrollbars.
You could adjust the .Height of the TextBox when its .Text changes:
Public Class Form1
Dim txt As TextBox
Sub maketb()
txt = New TextBox
txt.Multiline = True
txt.Size = New Size(100, 50)
txt.WordWrap = True
txt.Location = New Point(10, 10)
Me.Controls.Add(txt)
End Sub
Sub SetHeight(sender As Object, e As EventArgs)
Dim target = DirectCast(sender, TextBox)
Dim fn = target.Font
Dim gr = target.CreateGraphics()
Dim lrMarginSize = target.Margin.Left + target.Margin.Right
Dim tbMarginSize = target.Margin.Top + target.Margin.Bottom
Dim h = gr.MeasureString(target.Text, fn, target.Width - lrMarginSize).Height + tbMarginSize
target.Height = CInt(Math.Ceiling(h))
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
maketb()
AddHandler txt.TextChanged, AddressOf SetHeight
txt.Text = "dfgd dfd gg hgljhhkjlh jhkkj hkjh hghjg hgjhgz hfjsdhfytu hgjahg ht gretyt jgagury agha gty ajhg ajgx"
End Sub
End Class
Guys I have to apologize.
The error was in my xml (I had MultiLine instead of Multiline), so my textbox was never Multiline.
Thanks for your time, Sorry for spending it without meaning.