文本框中只能输入数字

1 同上上篇日志  老师给的代码

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        Dim c As Char
        c = e.KeyChar
        If c = "."c Then
            If InStr(TextBox1.Text, e.KeyChar) > 0 Or (InStr(TextBox1.Text, "-") > 0) And (TextBox1.SelectionStart = 0) Then
                e.KeyChar = ""
            End If
        ElseIf c = "-"c Then
            If InStr(TextBox1.Text, c) > 0 Or TextBox1.SelectionStart > 0 Then
                e.KeyChar = ""
            End If
        ElseIf c = "0"c Then
            If (TextBox1.SelectionStart = 0 And Not TextBox1.Text.StartsWith("0") And TextBox1.Text.Length <> 0) Or (TextBox1.SelectionStart <= 1 And TextBox1.Text.StartsWith("0")) Then
                e.KeyChar = ""
            End If
        ElseIf c = ControlChars.Back Then
        ElseIf InStr("123456789", e.KeyChar) <= 0 Then
            e.KeyChar = ""
        End If
    End Sub

说实话看的不是太懂=_+

2. 控制键盘只能输入数字//未验证

private   void   textBox3_KeyPress(object sender,System.Windows.Forms.KeyPressEventArgs e) 
{ 
//阻止从键盘输入键 
e.Handled = true; 
if(e.KeyChar> =48 && e.KeyChar<=57) 
  { 
   e.Handled  = false; 
  } 
} 

3.参考网页：http://hi.baidu.com/pepsisoft/blog/item/d8664327bb011c03908f9d2c.html  //这个我看懂了=_+

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Textbox1.KeyPress
    If Char.IsDigit(e.KeyChar) Or e.KeyChar = "." Or e.KeyChar = Chr(8) Then
        If e.KeyChar = "." And InStr(TextBox1.Text, ".") > 0 Then
            e.Handled = True
         Else
             e.Handled = False
         End If
     ElseIf e.KeyChar = "-" And TextBox1.Text = "" Then
         e.Handled = False
     Else
         e.Handled = True
     End If
End Sub

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另有一帖子是搜keychar搜到的，关于Datagrid键盘事件响应。

http://www.newasp.net/tech/net/10081.html