コンボ ボックスのドロップダウン部分の幅を取得または設定します。
Public Property DropDownWidth As Integer
[C#]
public int DropDownWidth {get; set;}
[C++]
public: __property int get_DropDownWidth();public: __property void set_DropDownWidth(int);
[JScript]
public function get DropDownWidth() : int;public function set DropDownWidth(int);
プロパティ値
ドロップダウン ボックスの幅 (ピクセル単位)。
例外
| 例外の種類 | 条件 |
|---|---|
| ArgumentException | 指定された値が 1 未満です。 |
解説
DropDownWidth に値が設定されていない場合は、このプロパティがコンボ ボックスの Width を返します。
メモ ドロップダウンの幅を ComboBox の幅より小さくすることはできません。
使用例
[Visual Basic, C#] DrawMode プロパティを OwnerDrawnVariable に設定し、 DrawItem イベントおよび MeasureItem イベントを処理して、オーナー描画のコンボ ボックスを作成するコード例を次に示します。この例はまた、 DropDownWidth プロパティおよび DropDownStyle プロパティの設定方法も示しています。この例を実行するには、次のコードをフォームに貼り付けます。そして、フォームのコンストラクタまたは Load メソッドで InitializeComboBox メソッドを呼び出します。
Friend WithEvents ComboBox1 As System.Windows.Forms.ComboBox
Private animals() As String
' This method initializes the owner-drawn combo box.
' The drop-down width is set much wider than the size of the combo box
' to accomodate the large items in the list. The drop-down style is set to
' ComboBox.DropDown, which requires the user to click on the arrow to
' see the list.
Private Sub InitializeComboBox()
Me.ComboBox1 = New ComboBox
Me.ComboBox1.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawVariable
Me.ComboBox1.Location = New System.Drawing.Point(10, 20)
Me.ComboBox1.Name = "ComboBox1"
Me.ComboBox1.Size = New System.Drawing.Size(100, 120)
Me.ComboBox1.DropDownWidth = 250
Me.ComboBox1.TabIndex = 0
Me.ComboBox1.DropDownStyle = ComboBoxStyle.DropDown
animals = New String() {"Elephant", "c r o c o d i l e", "lion"}
ComboBox1.DataSource = animals
Me.Controls.Add(Me.ComboBox1)
End Sub
' If you set the Draw property to DrawMode.OwnerDrawVariable,
' you must handle the MeasureItem event. This event handler
' will set the height and width of each item before it is drawn.
Private Sub ComboBox1_MeasureItem(ByVal sender As Object, _
ByVal e As System.Windows.Forms.MeasureItemEventArgs) _
Handles ComboBox1.MeasureItem
Select Case e.Index
Case 0
e.ItemHeight = 45
Case 1
e.ItemHeight = 20
Case 2
e.ItemHeight = 35
End Select
e.ItemWidth = 260
End Sub
' You must handle the DrawItem event for owner-drawn combo boxes.
' This event handler changes the color, size and font of an
' item based on its position in the array.
Protected Sub ComboBox1_DrawItem(ByVal sender As Object, _
ByVal e As System.Windows.Forms.DrawItemEventArgs) _
Handles ComboBox1.DrawItem
Dim size As Single
Dim myFont As System.Drawing.Font
Dim family As FontFamily
Dim animalColor As New System.Drawing.Color
Select Case e.Index
Case 0
size = 30
animalColor = System.Drawing.Color.Gray
family = FontFamily.GenericSansSerif
Case 1
size = 10
animalColor = System.Drawing.Color.LawnGreen
family = FontFamily.GenericMonospace
Case 2
size = 15
animalColor = System.Drawing.Color.Tan
family = FontFamily.GenericSansSerif
End Select
' Draw the background of the item.
e.DrawBackground()
' Create a square filled with the animals color. Vary the size
' of the rectangle based on the length of the animals name.
Dim rectangle As Rectangle = New Rectangle(2, e.Bounds.Top + 2, _
e.Bounds.Height, e.Bounds.Height - 4)
e.Graphics.FillRectangle(New SolidBrush(animalColor), rectangle)
' Draw each string in the array, using a different size, color,
' and font for each item.
myFont = New Font(family, size, FontStyle.Bold)
e.Graphics.DrawString(animals(e.Index), myFont, System.Drawing.Brushes.Black, _
New RectangleF(e.Bounds.X + rectangle.Width, e.Bounds.Y, _
e.Bounds.Width, e.Bounds.Height))
' Draw the focus rectangle if the mouse hovers over an item.
e.DrawFocusRectangle()
End Sub
[C#]
internal System.Windows.Forms.ComboBox ComboBox1;
private string[] animals;
// This method initializes the owner-drawn combo box.
// The drop-down width is set much wider than the size of the combo box
// to accomodate the large items in the list. The drop-down style is set to
// ComboBox.DropDown, which requires the user to click on the arrow to
// see the list.
private void InitializeComboBox()
{
this.ComboBox1 = new ComboBox();
this.ComboBox1.DrawMode =
System.Windows.Forms.DrawMode.OwnerDrawVariable;
this.ComboBox1.Location = new System.Drawing.Point(10, 20);
this.ComboBox1.Name = "ComboBox1";
this.ComboBox1.Size = new System.Drawing.Size(100, 120);
this.ComboBox1.DropDownWidth = 250;
this.ComboBox1.TabIndex = 0;
this.ComboBox1.DropDownStyle = ComboBoxStyle.DropDown;
animals = new string[]{"Elephant", "c r o c o d i l e", "lion"};
ComboBox1.DataSource = animals;
this.Controls.Add(this.ComboBox1);
// Hook up the MeasureItem and DrawItem events
this.ComboBox1.DrawItem +=
new DrawItemEventHandler(ComboBox1_DrawItem);
this.ComboBox1.MeasureItem +=
new MeasureItemEventHandler(ComboBox1_MeasureItem);
}
// If you set the Draw property to DrawMode.OwnerDrawVariable,
// you must handle the MeasureItem event. This event handler
// will set the height and width of each item before it is drawn.
private void ComboBox1_MeasureItem(object sender,
System.Windows.Forms.MeasureItemEventArgs e)
{
switch(e.Index)
{
case 0:
e.ItemHeight = 45;
break;
case 1:
e.ItemHeight = 20;
break;
case 2:
e.ItemHeight = 35;
break;
}
e.ItemWidth = 260;
}
// You must handle the DrawItem event for owner-drawn combo boxes.
// This event handler changes the color, size and font of an
// item based on its position in the array.
protected void ComboBox1_DrawItem(object sender,
System.Windows.Forms.DrawItemEventArgs e)
{
float size = 0;
System.Drawing.Font myFont;
FontFamily family = null;
System.Drawing.Color animalColor = new System.Drawing.Color();
switch(e.Index)
{
case 0:
size = 30;
animalColor = System.Drawing.Color.Gray;
family = FontFamily.GenericSansSerif;
break;
case 1:
size = 10;
animalColor = System.Drawing.Color.LawnGreen;
family = FontFamily.GenericMonospace;
break;
case 2:
size = 15;
animalColor = System.Drawing.Color.Tan;
family = FontFamily.GenericSansSerif;
break;
}
// Draw the background of the item.
e.DrawBackground();
// Create a square filled with the animals color. Vary the size
// of the rectangle based on the length of the animals name.
Rectangle rectangle = new Rectangle(2, e.Bounds.Top+2,
e.Bounds.Height, e.Bounds.Height-4);
e.Graphics.FillRectangle(new SolidBrush(animalColor), rectangle);
// Draw each string in the array, using a different size, color,
// and font for each item.
myFont = new Font(family, size, FontStyle.Bold);
e.Graphics.DrawString(animals[e.Index], myFont, System.Drawing.Brushes.Black, new RectangleF(e.Bounds.X+rectangle.Width, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height));
// Draw the focus rectangle if the mouse hovers over an item.
e.DrawFocusRectangle();
}
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をクリックします。
必要条件
プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ