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ComboBox.DropDownStyle Property

Gets or sets a value specifying the style of the combo box.

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

'Declaration
Public Property DropDownStyle As ComboBoxStyle

Property Value

Type: System.Windows.Forms.ComboBoxStyle
One of the ComboBoxStyle values. The default is DropDown.

ExceptionCondition
InvalidEnumArgumentException

The assigned value is not one of the ComboBoxStyle values.

The DropDownStyle property specifies whether the list is always displayed or whether the list is displayed in a drop-down. The DropDownStyle property also specifies whether the text portion can be edited. See ComboBoxStyle for the available settings and their effects. There is no setting to always display the list and disallow entering a new value. To display a list to which no new values can be added, use a ListBox control.

The following code example demonstrates setting the DropDownStyle property. To run the example, paste the following code in a form. Call the InitializeComboBox method in the form's constructor or Load event.

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. 
    Private 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

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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