VB.Net 验证：检查文本是否仅包含字母
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VB.Net Validation: Checking if Text Contains Only Letters
提问by Jason
Need to know how to validate a Text Box's text to make sure it contains ONLY letters without spaces.
需要知道如何验证文本框的文本以确保它只包含没有空格的字母。
I was hoping some sort of functions exists which could help me, something like "IsString" or something.
我希望存在某种可以帮助我的函数，例如“IsString”之类的。
回答by Alex K.
Use a Regular Expression
使用正则表达式
if System.Text.RegularExpressions.Regex.IsMatch(TextBox.Text, "^[A-Za-z]+$")) ...
Edit
编辑
The ^ $character are anchors; they mean match the startand end-of-linerespectively and can be used to prevent sub-string/partial matches.
该^ $角色是锚; 它们意味着匹配开始和结束时的线分别和可用于防止子串/部分匹配。
E.g. The regex Xwould match "X"and "AAAXAAA"but ^X$only matches "X"as its value can be thought of as "<start of line>X<end of line>"
例如，正则表达式X将匹配"X"，"AAAXAAA"但^X$仅匹配"X"为它的值可以被认为是"<start of line>X<end of line>"
回答by Justin Ryan
This will prevent anything from being typed into the TextBox except letters.
这将防止在 TextBox 中输入除字母以外的任何内容。
Private Sub TextBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox.KeyPress
If Not Char.IsLetter(e.KeyChar) Then e.Handled = True 'ignore everything but letter keys
End Sub
回答by Missing_Link
To make it simple:
为了简单起见：
Char.isletter(textboxname)
If char.isletter(textboxname)=false then
Msgbox(error message)
Textboxname.clear()
Textboxname.focus()
End if
回答by rory.ap
You can use a regular expression, like this:
您可以使用正则表达式，如下所示：
Return (New System.Text.RegularExpressions.Regex("^[a-zA-Z]{1,}$")).IsMatch(testValue)
