ListBox.DrawMode 属性

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

获取或设置控件的绘图模式。

public:
 virtual property System::Windows::Forms::DrawMode DrawMode { System::Windows::Forms::DrawMode get(); void set(System::Windows::Forms::DrawMode value); };

public virtual System.Windows.Forms.DrawMode DrawMode { get; set; }

member this.DrawMode : System.Windows.Forms.DrawMode with get, set

Public Overridable Property DrawMode As DrawMode

属性值

DrawMode

DrawMode 值之一，表示用于绘制控件的项的模式。 默认值为 DrawMode.Normal。

例外

InvalidEnumArgumentException

分配给属性的值不是 DrawMode 枚举的成员。

ArgumentException

多列 ListBox 的高度不能变化。

示例

下面的代码示例演示如何创建所有者绘制 ListBox 的项。 代码使用 DrawMode 属性指定绘制的项大小固定，以及 DrawItem 执行将每个项绘制到 中的 ListBox事件。 示例代码使用作为参数传递给事件处理程序的 DrawItemEventArgs 类的属性和方法来绘制项。 此示例要求 ListBox 已将名为 的 listBox1 控件添加到窗体中， DrawItem 并且该事件由示例代码中定义的事件处理程序处理。 该示例还要求已按该顺序将 ListBox 文本为“Apple”、“Orange”和“Plum”的项添加到 。

private ListBox ListBox1 = new ListBox();
private void InitializeListBox()
{
    ListBox1.Items.AddRange(new Object[] 
        { "Red Item", "Orange Item", "Purple Item" });
    ListBox1.Location = new System.Drawing.Point(81, 69);
    ListBox1.Size = new System.Drawing.Size(120, 95);
    ListBox1.DrawMode = DrawMode.OwnerDrawFixed;
    ListBox1.DrawItem += new DrawItemEventHandler(ListBox1_DrawItem);
    Controls.Add(ListBox1);
}

private void ListBox1_DrawItem(object sender, 
    System.Windows.Forms.DrawItemEventArgs e)
{
    // Draw the background of the ListBox control for each item.
    e.DrawBackground();
    // Define the default color of the brush as black.
    Brush myBrush = Brushes.Black;

    // Determine the color of the brush to draw each item based 
    // on the index of the item to draw.
    switch (e.Index)
    {
        case 0:
            myBrush = Brushes.Red;
            break;
        case 1:
            myBrush = Brushes.Orange;
            break;
        case 2:
            myBrush = Brushes.Purple;
            break;
    }

    // Draw the current item text based on the current Font 
    // and the custom brush settings.
    e.Graphics.DrawString(ListBox1.Items[e.Index].ToString(), 
        e.Font, myBrush, e.Bounds, StringFormat.GenericDefault);
    // If the ListBox has focus, draw a focus rectangle around the selected item.
    e.DrawFocusRectangle();
}

Private WithEvents ListBox1 As New ListBox()

Private Sub InitializeListBox() 
    ListBox1.Items.AddRange(New Object() _
        {"Red Item", "Orange Item", "Purple Item"})
    ListBox1.Location = New System.Drawing.Point(81, 69)
    ListBox1.Size = New System.Drawing.Size(120, 95)
    ListBox1.DrawMode = DrawMode.OwnerDrawFixed
    Controls.Add(ListBox1)

End Sub

Private Sub ListBox1_DrawItem(ByVal sender As Object, _
 ByVal e As System.Windows.Forms.DrawItemEventArgs) _
 Handles ListBox1.DrawItem

    ' Draw the background of the ListBox control for each item.
    e.DrawBackground()

    ' Define the default color of the brush as black.
    Dim myBrush As Brush = Brushes.Black

    ' Determine the color of the brush to draw each item based on   
    ' the index of the item to draw.
    Select Case e.Index
        Case 0
            myBrush = Brushes.Red
        Case 1
            myBrush = Brushes.Orange
        Case 2
            myBrush = Brushes.Purple
    End Select

    ' Draw the current item text based on the current 
    ' Font and the custom brush settings.
    e.Graphics.DrawString(ListBox1.Items(e.Index).ToString(), _
        e.Font, myBrush, e.Bounds, StringFormat.GenericDefault)

    ' If the ListBox has focus, draw a focus rectangle around  _ 
    ' the selected item.
    e.DrawFocusRectangle()
End Sub

另请参阅

• DrawMode
• DrawItem