Visual Basic 2005——如何在DataGridView控件的储存格中同时显示出文字与图片

上次有读者说我写得太简单，那么我们今天就写个难一点的吧！很多用户询问，如何如图1所示，在DataGridView控件的储存格中同时显示出图片与文字。

 

图1

 

DataGridView控件并没有内建任何功能来让您在同一个储存格中显示出图片与文字。解决之道，是通过CellPaint等事件来完成自订的绘制作业。

 

以下我们建立一个衍生自DataGridViewTextBoxColumn的用户自订数据行类别，藉此于储存格内的文字旁边绘制一个图片。我们使用DataGridViewCellStyle.Padding属性来调整文字位置并重写Paint方法以便绘制一个图片：

 

Public Class TextAndImageColumn
    Inherits DataGridViewTextBoxColumn

    Private _imageValue As Image
    Private _imageSize As Size

    Public Sub New()
        MyBase.New()
        Me.CellTemplate = New TextAndImageCell
        Me.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight
    End Sub

    Public Property Image() As Image
        Get
            Return Me._imageValue
        End Get
        Set(ByVal value As Image)
            Me._imageValue = value
            Me._imageSize = value.Size
            If Me.InheritedStyle IsNot Nothing Then
                Dim inheritedPadding As Padding = Me.InheritedStyle.Padding
                Me.DefaultCellStyle.Padding = New Padding( _

                  ImageSize.Width, inheritedPadding.Top, _

                  inheritedPadding.Right, inheritedPadding.Bottom)
            End If          
        End Set
    End Property

    Private ReadOnly Property TextAndImageCellTemplate() As TextAndImageCell
        Get
            Return CType(Me.CellTemplate, TextAndImageCell)
        End Get
    End Property

    Friend ReadOnly Property ImageSize() As Size
        Get
            Return ImageSize
        End Get
    End Property

    Public Overrides Function Clone() As Object
        Dim c As TextAndImageColumn = CType(MyBase.Clone, TextAndImageColumn)
        c._imageValue = Me._imageValue
        c._imageSize = Me.ImageSize
        Return c
    End Function
End Class

Public Class TextAndImageCell
    Inherits DataGridViewTextBoxCell

    Private imageValue As Image
    Private imageSize As Size

    Public Property Image() As Image
        Get
            If ((Me.OwningColumn Is Nothing) _
                      OrElse (Me.OwningTextAndImageColumn Is Nothing)) Then
                Return imageValue
            ElseIf (Me.imageValue IsNot Nothing) Then
                Return Me.imageValue
            Else
                Return Me.OwningTextAndImageColumn.Image
            End If
        End Get
        Set(ByVal value As Image)
            If Not Me.imageValue.Equals(value) Then
                Me.imageValue = value
                Me.imageSize = value.Size
                Dim inheritedPadding As Padding = Me.InheritedStyle.Padding
                Me.Style.Padding = New Padding( _
                  imageSize.Width, inheritedPadding.Top, _
                  inheritedPadding.Right, inheritedPadding.Bottom)
            End If
        End Set
    End Property

    Private ReadOnly Property OwningTextAndImageColumn() As TextAndImageColumn
        Get
            Return CType(Me.OwningColumn, TextAndImageColumn)
        End Get
    End Property

    Public Overrides Function Clone() As Object
        Dim c As TextAndImageCell = CType(MyBase.Clone, TextAndImageCell)
        c.imageValue = Me.imageValue
        c.imageSize = Me.imageSize
        Return c
    End Function

    Protected Overrides Sub Paint(ByVal graphics As Graphics, _

      ByVal clipBounds As Rectangle, ByVal cellBounds As Rectangle, _

      ByVal rowIndex As Integer, _

      ByVal cellState As DataGridViewElementStates, _

      ByVal value As Object, ByVal formattedValue As Object, _

      ByVal errorText As String, ByVal cellStyle As DataGridViewCellStyle, _

      ByVal advancedBorderStyle As DataGridViewAdvancedBorderStyle, _

      ByVal paintParts As DataGridViewPaintParts)

      MyBase.Paint(graphics, clipBounds, cellBounds, rowIndex, _

        cellState, value, formattedValue, errorText, cellStyle, _

        advancedBorderStyle, paintParts)
        If (Not (Me.Image) Is Nothing) Then
            Dim container As System.Drawing.Drawing2D.GraphicsContainer = _

              graphics.BeginContainer
            graphics.SetClip(cellBounds)
            graphics.DrawImageUnscaled(Me.Image, cellBounds.Location)
            graphics.EndContainer(container)
        End If
    End Sub
End Class

 

 

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