[RESOLVED] Invoking many controls

[steve_rm]

Hello,

The function below will be called from another thread. So the control themselves will have to be invoked so that the correct thread that created them can change the properties.

However, as I have many controls that need to be updated. I don't really want to write all those delegates for each one. I have done one below. However, I am thinking that is a lot of code. Is there anyway to shorten this?

Many thanks,

Public Sub SetIdleState(ByVal callStatusMsg As String)
			Me.btnCallAnswer.Text = CATWinSIP_MsgStrings.Call
			Me.btnEndCallReject.Text = CATWinSIP_MsgStrings.EndCall
			Me.btnHoldUnhold.Text = CATWinSIP_MsgStrings.Hold

			Me.btnCallAnswer.Enabled = True
			Me.btnRedial.Enabled = True
			Me.btnEndCallReject.Enabled = False
			Me.btnHoldUnhold.Enabled = False

			If Me.statusDisplay1.InvokeRequired Then
				statusDisplay1.Invoke(New UpdateCallStatusDelegate(AddressOf Me.UpdateCallStatus), callStatusMsg)
			Else
			   Me.statusDisplay1.CallStatus = callStatusMsg
			End If
End Sub

		' Delegate for marshalling the call on the correct thread.
		Private Delegate Sub UpdateCallStatusDelegate(ByVal callStatusMsg As String)
		Private Sub UpdateCallStatus(ByVal callStatusMsg As String)
			Me.statusDisplay1.CallStatus = callStatusMsg
		End Sub

[jmcilhinney]

I don't understand your code. The fact that you're testing InvokeRequired in your SetIdleState method implies that that method is called on a secondary thread, yet you're accessing multiple controls in that method. Have you read the Controls & Multi-threading thread of mine in the CodeBank? It outlines a number of steps you can perform and those steps NEVER change. The fact that you have multiple controls to access is irrelevant. The steps are:

1. Write a method that does what you need:

Public Sub SetIdleState(ByVal callStatusMsg As String)
    Me.btnCallAnswer.Text = CATWinSIP_MsgStrings.Call
    Me.btnEndCallReject.Text = CATWinSIP_MsgStrings.EndCall
    Me.btnHoldUnhold.Text = CATWinSIP_MsgStrings.Hold
 
    Me.btnCallAnswer.Enabled = True
    Me.btnRedial.Enabled = True
    Me.btnEndCallReject.Enabled = False
    Me.btnHoldUnhold.Enabled = False
 
    Me.statusDisplay1.CallStatus = callStatusMsg
End Sub

2. Test the InvokeRequired property of a control, moving the current contents of the method into the Else block:

Public Sub SetIdleState(ByVal callStatusMsg As String)
    If Me.InvokeRequired Then
 
    Else
        Me.btnCallAnswer.Text = CATWinSIP_MsgStrings.Call
        Me.btnEndCallReject.Text = CATWinSIP_MsgStrings.EndCall
        Me.btnHoldUnhold.Text = CATWinSIP_MsgStrings.Hold
 
        Me.btnCallAnswer.Enabled = True
        Me.btnRedial.Enabled = True
        Me.btnEndCallReject.Enabled = False
        Me.btnHoldUnhold.Enabled = False
 
        Me.statusDisplay1.CallStatus = callStatusMsg
    End If
End Sub

3. Create a delegate by copying the method declaration, changing the name and adding the Delegate key word:

Public Delegate Sub SetIdleStateInvoker(ByVal callStatusMsg As String)
 
Public Sub SetIdleState(ByVal callStatusMsg As String)
    If Me.InvokeRequired Then
 
    Else
        Me.btnCallAnswer.Text = CATWinSIP_MsgStrings.Call
        Me.btnEndCallReject.Text = CATWinSIP_MsgStrings.EndCall
        Me.btnHoldUnhold.Text = CATWinSIP_MsgStrings.Hold
 
        Me.btnCallAnswer.Enabled = True
        Me.btnRedial.Enabled = True
        Me.btnEndCallReject.Enabled = False
        Me.btnHoldUnhold.Enabled = False
 
        Me.statusDisplay1.CallStatus = callStatusMsg
    End If
End Sub

In the If block, invoke the current method using an instance of the delegate you just declared:

Public Delegate Sub SetIdleStateInvoker(ByVal callStatusMsg As String)
 
Public Sub SetIdleState(ByVal callStatusMsg As String)
    If Me.InvokeRequired Then
        Me.Invoke(New SetIdleStateInvoker(AddressOf SetIdleState), _
                  callStatusMsg)
    Else
        Me.btnCallAnswer.Text = CATWinSIP_MsgStrings.Call
        Me.btnEndCallReject.Text = CATWinSIP_MsgStrings.EndCall
        Me.btnHoldUnhold.Text = CATWinSIP_MsgStrings.Hold
 
        Me.btnCallAnswer.Enabled = True
        Me.btnRedial.Enabled = True
        Me.btnEndCallReject.Enabled = False
        Me.btnHoldUnhold.Enabled = False
 
        Me.statusDisplay1.CallStatus = callStatusMsg
    End If
End Sub