Dynamic button click event handler

Question

I ve 100 buttons created dynamically in a form  How can I an add event handler to them

User · Answer

Just to round out Reed s answer  you can either get the Button objects from the Form or other container and add the handler  or you could create the Button objects programmatically  If you get the Button objects from the Form or other container  then you can iterate over the Controls collection of the Form or other container control  such as Panel or FlowLayoutPanel and so on  You can then just add the click handler with AddHandler ctrl Click  AddressOf Me Button Click  variables as in the code below   but I prefer to check the type of the Control and cast to a Button so as I m not adding click handlers for any other controls in the container  such as Labels   Remember that you can add handlers for any event of the Button at this point using AddHandler  Alternatively  you can create the Button objects programmatically  as in the second block of code below  Then  of course  you have to write the handler method  as in the third code block below   Here is an example using Form as the container  but you re probably better off using a Panel or some other container control    Dim btn as Button   Nothing For Each ctrl As Control in myForm Controls     If TypeOf ctrl Is Button Then         btn   DirectCast ctrl  Button          AddHandler btn Click  AddressOf Me Button Click     From answer by Reed      End If  Next   Alternatively creating the Buttons  programmatically  this time adding to a Panel container    Dim Panel1 As new Panel   For i As Integer   1 to 100     btn   New Button         Set Button properties or call a method to do so      Panel1 Controls Add btn     Add Button to the container      AddHandler btn Click  AddressOf Me Button Click     Again from the answer by Reed  Next   Then your handler will look something like this   Private Sub Button Click ByVal sender As System Object  ByVal e As System EventArgs        Handle your Button clicks here End Sub

User · Answer

Some code for a variation on this problem  Using the above code got me my click events as needed  but I was then stuck trying to work out which button had been clicked  My scenario is I have a dynamic amount of tab pages  On each tab page are  all dynamically created  2 charts  2 DGVs and a pair of radio buttons  Each control has a unique name relative to the tab  but there could be 20 radio buttons with the same name if I had 20 tab pages  The radio buttons switch between which of the 2 graphs and DGVs you get to see  Here is the code for when one of the radio buttons gets checked  There s a nearly identical block that swaps the charts and DGVs back       Private Sub radioFit Components CheckedChanged ByVal sender As System Object  ByVal e As System EventArgs       If sender name    radioFit Components  And sender visible Then         If sender checked Then             For Each ctrl As Control In TabControl1 SelectedTab Controls                 Select Case ctrl Name                     Case  embChartSSE Components                          ctrl BringToFront                       Case  embChartSSE Fit Curve                          ctrl SendToBack                       Case  dgvFit Components                          ctrl BringToFront                   End Select             Next          End If     End If  End Sub   This code will fire for any of the tab pages and swap the charts and DGVs over on any of the tab pages  The sender visible check is to stop the code firing when the form is being created

User · Answer

I needed a common event handler in which I can show from which button it is called without  using switch case    and done like this      Private Sub btn done clicked ByVal sender As System Object  ByVal e As System EventArgs       MsgBox Show  you have clicked button    amp  CType CType sender         System Windows Forms Button  Tag  String      End Sub

User · Answer

You can use AddHandler to add a handler for any event   For example  this might be   AddHandler theButton Click  AddressOf Me theButton Click

User · Answer

Debasish Sahu  your answer is an answer to another question  namely  how to know which button  or any other control  was clicked when there is a common handler for a couple of controls  So I m giving an answer to this question how I usually do it  almost the same as yours  but note that also works without type conversion when it handles the same type of Controls   Private Sub btn done clicked ByVal sender As System Object  ByVal e As System EventArgs      Dim selectedBtn As Button   sender     MsgBox  you have clicked button    amp  selectedBtn Name  End Sub

[vb.net] Dynamic button click event handler

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