如何只允许字符值? [英] how to allow only character value ?
本文介绍了如何只允许字符值?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
公开 类 Form1
私有 Sub Button1_Click( ByVal sender 作为系统。对象, ByVal e As System.EventArgs)句柄 Button1.Click
If TextBox1.Text<> 然后
ListBox1 .Items.Add(TextBox1.Text)
TextBox1.Text =
结束 如果
结束 Sub
结束 类
解决方案
方法1
< span class =code-keyword>私有 Sub Button1_Click( ByVal sender 作为系统。对象, ByVal e As System.EventArgs)句柄 Button1.Click
如果 TextBox1.Text.Trim<> 然后
< span class =code-keyword>如果 Char .IsLetter( Me .TextBox1。文本)然后
ListBox1.Items.Add(TextBox1.Text)
TextBox1.Text =
其他
MsgBox( 请仅输入字符,MsgBoxStyle.Exclamation, 字符提示)
结束 如果
结束 如果
结束 Sub
方法2
私有 Sub Button1_Click( ByVal sender As System。 Object , ByVal e As System.EventArgs)句柄 Button1.Click
如果 TextBox1.Text.Trim<> 然后
ListBox1 .Items.Add(TextBox1.Text)
TextBox1.Text =
结束 如果
结束 Sub
私有 Sub TextBox1_KeyPress( ByVal sender As Object , ByVal e As System.Windows.Forms.KeyPressEventArgs)句柄 TextBox1.KeyPress
Check_character(e)
结束 Sub
Sub Check_character( ByVal e As System.Windows.Forms.KeyPressEventArgs)
如果 Char .IsLetter(e .KeyChar)= False 和(Asc(e.KeyChar)<> 13 )和(Asc(e.KeyChar)<> 8 )和 字符 .IsWhiteSpace(e.KeyChar)= False 然后
e.Handled = True
MsgBox( 仅允许字符,MsgBoxStyle.Exclamation, 字符提示)
结束 如果
结束 Sub
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If TextBox1.Text <> " " Then
ListBox1.Items.Add(TextBox1.Text)
TextBox1.Text = " "
End If
End Sub
End Class
解决方案
Method 1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click If TextBox1.Text.Trim <> "" Then If Char.IsLetter(Me.TextBox1.Text) Then ListBox1.Items.Add(TextBox1.Text) TextBox1.Text = "" Else MsgBox("Please enter characters only", MsgBoxStyle.Exclamation, "Character Alert") End If End If End Sub
Method 2
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click If TextBox1.Text.Trim <> "" Then ListBox1.Items.Add(TextBox1.Text) TextBox1.Text = "" End If End Sub Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress Check_character(e) End Sub Sub Check_character(ByVal e As System.Windows.Forms.KeyPressEventArgs) If Char.IsLetter(e.KeyChar) = False And (Asc(e.KeyChar) <> 13) And (Asc(e.KeyChar) <> 8) And Char.IsWhiteSpace(e.KeyChar) = False Then e.Handled = True MsgBox("Only Characters Allowed", MsgBoxStyle.Exclamation, "Character Alert") End If End Sub
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