Rediger

Del via

Control.HasChildren Property

  • Reference

Definition

Namespace:
System.Windows.Forms
Assembly:
System.Windows.Forms.dll

Gets a value indicating whether the control contains one or more child controls.

public:
 property bool HasChildren { bool get(); };
[System.ComponentModel.Browsable(false)]
public bool HasChildren { get; }
[<System.ComponentModel.Browsable(false)>]
member this.HasChildren : bool
Public ReadOnly Property HasChildren As Boolean

Property Value

Boolean

true if the control contains one or more child controls; otherwise, false.

Attributes
BrowsableAttribute

Examples

The following code example sets the BackColor and ForeColor of the controls to the default system colors. The code recursively calls itself if the control has any child controls. This code example requires that you have a Form with at least one child control; however, a child container control, like a Panel or GroupBox, with its own child control(s) would better demonstrate the recursion.

   // Reset all the controls to the user's default Control color.
private:
   void ResetAllControlsBackColor( Control^ control )
   {
      control->BackColor = SystemColors::Control;
      control->ForeColor = SystemColors::ControlText;
      if ( control->HasChildren )
      {
         // Recursively call this method for each child control.
         IEnumerator^ myEnum = control->Controls->GetEnumerator();
         while ( myEnum->MoveNext() )
         {
            Control^ childControl = safe_cast<Control^>(myEnum->Current);
            ResetAllControlsBackColor( childControl );
         }
      }
   }

// Reset all the controls to the user's default Control color. 
private void ResetAllControlsBackColor(Control control)
{
   control.BackColor = SystemColors.Control;
   control.ForeColor = SystemColors.ControlText;
   if(control.HasChildren)
   {
      // Recursively call this method for each child control.
      foreach(Control childControl in control.Controls)
      {
         ResetAllControlsBackColor(childControl);
      }
   }
}

' Reset all the controls to the user's default Control color. 
Private Sub ResetAllControlsBackColor(control As Control)
   control.BackColor = SystemColors.Control
   control.ForeColor = SystemColors.ControlText
   If control.HasChildren Then
      ' Recursively call this method for each child control.
      Dim childControl As Control
      For Each childControl In  control.Controls
         ResetAllControlsBackColor(childControl)
      Next childControl
   End If
End Sub

Remarks

If the Controls collection has a Count greater than zero, the HasChildren property will return true. Accessing the HasChildren property does not force the creation of a Control.ControlCollection if the control has no children, so referencing this property can provide a performance benefit when walking a tree of controls.

Applies to

See also