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How to: Allow the Null State for a Check Box and a Toggle Button

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The following example uses the TripleState property to allow Null as a legal value of a CheckBox and a ToggleButton. The user controls the value of TripleState through ToggleButton2. The user can set the value of a CheckBox or ToggleButton based on the value of TripleState. However, when a control is set to Null, no event is fired.

To use this example, copy this sample code to the Script Editor of a form. To run the code you need to open the form so the Open event will activate. Make sure that the form contains:

  • A CheckBox named CheckBox1.

  • A ToggleButton named ToggleButton1.

  • A ToggleButton named ToggleButton2.

Sub Item_Open() 
 Set CheckBox1 = Item.GetInspector.ModifiedFormPages("P.2").Controls("CheckBox1") 
 Set ToggleButton1 = Item.GetInspector.ModifiedFormPages("P.2").Controls("ToggleButton1") 
 Set ToggleButton2 = Item.GetInspector.ModifiedFormPages("P.2").Controls("ToggleButton2") 
 
 CheckBox1.Caption = "Value is True" 
 CheckBox1.Value = True 
 CheckBox1.TripleState = False 
 
 ToggleButton1.Caption = "Value is True" 
 ToggleButton1.Value = True 
 ToggleButton1.TripleState = False 
 
 ToggleButton2.Value = False 
 ToggleButton2.Caption = "Triple State Off" 
End Sub 
 
Sub ToggleButton2_Click() 
 Set CheckBox1 = Item.GetInspector.ModifiedFormPages("P.2").Controls("CheckBox1") 
 Set ToggleButton1 = Item.GetInspector.ModifiedFormPages("P.2").Controls("ToggleButton1") 
 Set ToggleButton2 = Item.GetInspector.ModifiedFormPages("P.2").Controls("ToggleButton2") 
 
 If ToggleButton2.Value = True Then 
 ToggleButton2.Caption = "Triple State On" 
 CheckBox1.TripleState = True 
 ToggleButton1.TripleState = True 
 Else 
 ToggleButton2.Caption = "Triple State Off" 
 CheckBox1.TripleState = False 
 ToggleButton1.TripleState = False 
 End If 
End Sub 
 
Sub CheckBox1_Click() 
 Set CheckBox1 = Item.GetInspector.ModifiedFormPages("P.2").Controls("CheckBox1") 
 If IsNull(CheckBox1.Value) Then 
 CheckBox1.Caption = "Value is Null" 
 ElseIf CheckBox1.Value = False Then 
 CheckBox1.Caption = "Value is False" 
 ElseIf CheckBox1.Value = True Then 
 CheckBox1.Caption = "Value is True" 
 End If 
End Sub 
 
Sub ToggleButton1_Click() 
 Set ToggleButton1 = Item.GetInspector.ModifiedFormPages("P.2").Controls("ToggleButton1") 
 If IsNull(ToggleButton1.Value) Then 
 ToggleButton1.Caption = "Value is Null" 
 ElseIf ToggleButton1.Value = False Then 
 ToggleButton1.Caption = "Value is False" 
 ElseIf ToggleButton1.Value = True Then 
 ToggleButton1.Caption = "Value is True" 
 End If 
End Sub