Question

我这里有代码可以更改列表框突出显示的颜色。但是，当列表框为空时，会给出错误 InvalidArgument =值-1，对于'index'无效。参数名称：索引 表格将进入无响应状态。

    Private Sub BranchListBox_DrawItem(sender As Object, e As DrawItemEventArgs) Handles BranchListBox.DrawItem
        Dim mybrush As New System.Drawing.SolidBrush(Color.FromArgb(0, 177, 89))
        mybrush.Color = Color.FromArgb(0, 177, 89)


            Try
                e.DrawBackground()
                If (e.State And DrawItemState.Selected) = DrawItemState.Selected Then
                    e.Graphics.FillRectangle(mybrush, e.Bounds)
                End If
                Using b As New SolidBrush(e.ForeColor)
                    e.Graphics.DrawString(BranchListBox.GetItemText(BranchListBox.Items(e.Index)), e.Font, b, e.Bounds)
                End Using
                e.DrawFocusRectangle()
            Catch ex As Exception

                 ColorAppend(LogsBox, Color.Red, TimeOfDay.ToString("h:mm:ss") & SystemLog & ex.Message & Environment.NewLine)
                LogsBox.ScrollToCaret()
            End Try

    End Sub

有人可以帮助我吗？

Answer 1

如果没有ListBox.Item，则可以避免此事件：

Private Sub BranchListBox_DrawItem(sender As Object, e As DrawItemEventArgs) Handles BranchListBox.DrawItem

    'exit this event in case there is not valid index.
    If e.Index = -1 Then
        Exit Sub
    End If

    Dim mybrush As New System.Drawing.SolidBrush(Color.FromArgb(0, 177, 89))
    mybrush.Color = Color.FromArgb(0, 177, 89)

    Try
        e.DrawBackground()

        If (e.State And DrawItemState.Selected) = DrawItemState.Selected Then
            e.Graphics.FillRectangle(mybrush, e.Bounds)
        End If

        Using b As New SolidBrush(e.ForeColor)
            e.Graphics.DrawString(BranchListBox.GetItemText(BranchListBox.Items(e.Index)), e.Font, b, e.Bounds)
        End Using

        e.DrawFocusRectangle()
    Catch ex As Exception
        ColorAppend(LogsBox, Color.Red, TimeOfDay.ToString("h:mm:ss") & SystemLog & ex.Message & Environment.NewLine)
        LogsBox.ScrollToCaret()
    End Try
End Sub

VB.Net更改列表框上的突出显示颜色

1 个答案: