VB.NET中要刪除列表框中的多個選項，請問代碼如何編寫。我下面的代碼錯在哪里請指導(dǎo)，謝謝

For?i?=?List1.ListCount?-?1?To?0?Step?-1

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If?List1.Selected(i)?Then

List1.RemoveItem?(i)

End?If

Next?i

VB.NET列表框問題

有這個條件是為了避免 當列表沒有選項的時候 或者 有選項但沒有選中的時候 點擊刪除按鈕會引發(fā)錯誤 selectindex =-1 是沒有選中的時候默認值 而列表序號從0開始 刪除一個不存在的序號引發(fā)錯誤

vb.net編寫一個為列表框添加刪除選項的應(yīng)用程序，如果該字符串在列表框中，

Private Sub TextBox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress

If e.KeyChar.ToString() = Chr(13) Then

Dim str As String = TextBox1.Text

If Not ListBox1.Items.Contains(str) Then

ListBox1.Items.Add(str)

End If

End If

End Sub

Private Sub btn_Remove_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

If ListBox1.SelectedIndex 0 Then

ListBox1.Items.RemoveAt(ListBox1.SelectedIndex)

End If

End Sub

Private Sub btn_Clear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

ListBox1.Items.Clear()

End Sub

VB.NET 如何去掉 GroupBox 控件的邊框？

工程里面添加一個類，命名為myGroupBox，代碼如下：

Imports System.ComponentModel

Imports System.Drawing.Drawing2D

Public Class myGroupBox

Inherits GroupBox

Public Sub New()

MyBase.BackColor = Color.Transparent

End Sub

Browsable(False) _

Public Overrides Property BackColor() As Color

Get

Return MyBase.BackColor

End Get

Set(value As Color)

MyBase.BackColor = value

End Set

End Property

Private m_backColor As Color = Color.Transparent

Public Property ActualBackColor() As Color

Get

Return Me.m_backColor

End Get

Set(value As Color)

Me.m_backColor = value

End Set

End Property

Protected Overrides Sub OnPaint(e As PaintEventArgs)

Dim tSize As Size = TextRenderer.MeasureText(Me.Text, Me.Font)

Dim borderRect As Rectangle = e.ClipRectangle

borderRect.Y += tSize.Height / 2

borderRect.Height -= tSize.Height / 2

Dim gPath As GraphicsPath = CreatePath(0, borderRect.Y, CSng(Me.Width - 1), borderRect.Height - 1, 5, True, _

True, True, True)

e.Graphics.FillPath(New SolidBrush(ActualBackColor), gPath)

e.Graphics.DrawPath(New Pen(Me.BackColor), gPath)

borderRect.X += 6

borderRect.Y -= 7

e.Graphics.DrawString(Me.Text, Me.Font, New SolidBrush(Me.ForeColor), borderRect)

End Sub

Public Function CreatePath(x As Single, y As Single, width As Single, height As Single, radius As Single, _

RoundTopLeft As Boolean, RoundTopRight As Boolean, RoundBottomRight As Boolean, RoundBottomLeft As Boolean) As GraphicsPath

Dim xw As Single = x + width

Dim yh As Single = y + height

Dim xwr As Single = xw - radius

Dim yhr As Single = yh - radius

Dim xr As Single = x + radius

Dim yr As Single = y + radius

Dim r2 As Single = radius * 2

Dim xwr2 As Single = xw - r2

Dim yhr2 As Single = yh - r2

Dim p As New GraphicsPath()

p.StartFigure()

'Top Left Corner

If RoundTopLeft Then

p.AddArc(x, y, r2, r2, 180, 90)

Else

p.AddLine(x, yr, x, y)

p.AddLine(x, y, xr, y)

End If

'Top Edge

p.AddLine(xr, y, xwr, y)

'Top Right Corner

If RoundTopRight Then

p.AddArc(xwr2, y, r2, r2, 270, 90)

Else

p.AddLine(xwr, y, xw, y)

p.AddLine(xw, y, xw, yr)

End If

'Right Edge

p.AddLine(xw, yr, xw, yhr)

'Bottom Right Corner

If RoundBottomRight Then

p.AddArc(xwr2, yhr2, r2, r2, 0, 90)

Else

p.AddLine(xw, yhr, xw, yh)

p.AddLine(xw, yh, xwr, yh)

End If

'Bottom Edge

p.AddLine(xwr, yh, xr, yh)

'Bottom Left Corner

If RoundBottomLeft Then

p.AddArc(x, yhr2, r2, r2, 90, 90)

Else

p.AddLine(xr, yh, x, yh)

p.AddLine(x, yh, x, yhr)

End If

'Left Edge

p.AddLine(x, yhr, x, yr)

p.CloseFigure()

Return p

End Function

End Class

工具欄會出現(xiàn)一個myGroupBox控件，放入窗體，你會發(fā)現(xiàn)邊框沒了。

文章名稱：vb.net列表框移除 vb中怎么移除list所有項
文章源于：http://chinadenli.net/article32/dojjosc.html

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