Export (0) Print
Expand All
Expand Minimize

ScrollEventHandler Delegate

Represents the method that handles the Scroll event of a ScrollBar, TrackBar, or DataGrid.

[Visual Basic]
<Serializable>
Public Delegate Sub ScrollEventHandler( _
   ByVal sender As Object, _
   ByVal e As ScrollEventArgs _
)
[C#]
[Serializable]
public delegate void ScrollEventHandler(
   object sender,
   ScrollEventArgs e
);
[C++]
[Serializable]
public __gc __delegate void ScrollEventHandler(
   Object* sender,
   ScrollEventArgs* e
);

[JScript] In JScript, you can use the delegates in the .NET Framework, but you cannot define your own.

Parameters [Visual Basic, C#, C++]

The declaration of your event handler must have the same parameters as the ScrollEventHandler delegate declaration.

sender
The source of the event.
e
A ScrollEventArgs that contains the event data.

Remarks

When you create a ScrollEventArgs delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see Events and Delegates.

Example

[Visual Basic] 
Private Sub AddMyScrollEventHandlers()
    ' Create and initialize a VScrollBar.
    Dim vScrollBar1 As New VScrollBar()
    
    ' Add event handlers for the OnScroll and OnValueChanged events.
    AddHandler vScrollBar1.Scroll, AddressOf Me.vScrollBar1_Scroll
    AddHandler vScrollBar1.ValueChanged, AddressOf Me.vScrollBar1_ValueChanged
End Sub    

' Create the ValueChanged event handler.
Private Sub vScrollBar1_ValueChanged(sender As Object, e As EventArgs)
    ' Display the new value in the label.
    label1.Text = "vScrollBar Value:(OnValueChanged Event) " & _
        vScrollBar1.Value.ToString()
End Sub    

' Create the Scroll event handler.
Private Sub vScrollBar1_Scroll(sender As Object, e As ScrollEventArgs)
    ' Display the new value in the label.
    label1.Text = "VScrollBar Value:(OnScroll Event) " & _
        e.NewValue.ToString()
End Sub    

Private Sub button1_Click(sender As Object, e As EventArgs)
    ' Add 40 to the Value property if it will not exceed the Maximum value.
    If vScrollBar1.Value + 40 < vScrollBar1.Maximum Then
        vScrollBar1.Value = vScrollBar1.Value + 40
    End If
End Sub


[C#] 
private void AddMyScrollEventHandlers()
 {
    // Create and initialize a VScrollBar.
    VScrollBar vScrollBar1 = new VScrollBar();
 
    // Add event handlers for the OnScroll and OnValueChanged events.
    vScrollBar1.Scroll += new ScrollEventHandler(
       this.vScrollBar1_Scroll);
    vScrollBar1.ValueChanged += new EventHandler(
       this.vScrollBar1_ValueChanged); 
 }
 
 // Create the ValueChanged event handler.
 private void vScrollBar1_ValueChanged(Object sender, 
                                       EventArgs e)
 {
     // Display the new value in the label.
     label1.Text = "vScrollBar Value:(OnValueChanged Event) " + vScrollBar1.Value.ToString();
 }
 
 // Create the Scroll event handler.
 private void vScrollBar1_Scroll(Object sender, 
                                 ScrollEventArgs e)
 {
     // Display the new value in the label.
     label1.Text = "VScrollBar Value:(OnScroll Event) " + e.NewValue.ToString();
 }
 
 private void button1_Click(Object sender, 
                           EventArgs e)
 {
    // Add 40 to the Value property if it will not exceed the Maximum value.
    if (vScrollBar1.Value + 40 < vScrollBar1.Maximum)
    {
        vScrollBar1.Value = vScrollBar1.Value + 40;
    }
 }
 

[C++] 
private:
 void AddMyScrollEventHandlers()
 {
    // Create and initialize a VScrollBar.
    VScrollBar* vScrollBar1 = new VScrollBar();
 
    // Add event handlers for the OnScroll and OnValueChanged events.
    vScrollBar1->Scroll += new ScrollEventHandler(this, 
       &Form1::vScrollBar1_Scroll);
    vScrollBar1->ValueChanged += new EventHandler(this, 
       &Form1::vScrollBar1_ValueChanged); 
 }
 
 // Create the ValueChanged event handler.
 void vScrollBar1_ValueChanged(Object* /*sender*/, 
                               EventArgs* /*e*/)
 {
     // Display the new value in the label.
     label1->Text = String::Format( S"vScrollBar Value:(OnValueChanged Event) {0}",
         __box(vScrollBar1->Value));
 }
 
 // Create the Scroll event handler.
 void vScrollBar1_Scroll(Object* /*sender*/, 
                         ScrollEventArgs* e)
 {
     // Display the new value in the label.
     label1->Text = String::Format( S"VScrollBar Value:(OnScroll Event) {0}",
         __box(e->NewValue));
 }
 
 void button1_Click(Object* /*sender*/, 
                    EventArgs* /*e*/)
 {
    // Add 40 to the Value property if it will not exceed the Maximum value.
    if (vScrollBar1->Value + 40 < vScrollBar1->Maximum)
    {
        vScrollBar1->Value = vScrollBar1->Value + 40;
    }
 }
 

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Windows.Forms

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: System.Windows.Forms (in System.Windows.Forms.dll)

See Also

System.Windows.Forms Namespace | ScrollBar | TrackBar | DataGrid

Show:
© 2014 Microsoft