如何修复TextBox中的字符长度 [英] How to fix Character Length in a TextBox
问题描述
亲爱的朋友,
如何在文本框中修复字符长度?假设我想限制为3个三个字符。它不仅应输入少于或多于三个字符。其次,我想只允许文本框中的文本。请帮帮我。
1.要限制三个字符的文本框的最大长度,写一下
< asp:TextBox ID =TextBox1runat =serverMaxLength =3>< / asp:TextBox>
2.在文本框中正好匹配三个字符添加以下javascript函数
function checkLength(obj){
if (obj.value.length!= 3 ) {
alert( 应该是三个char。);
obj.focus();
}
}
并在onblur活动中调用该函数
TextBox1.Attributes.Add(onblur,checkLength(this));
3.仅允许文本框中的文本添加以下javascript函数
function handleKeydown(event){
keyEntry = event .keyCode || event.which;
if (
((keyEntry> = ' 65')&&(keyEntry< = ' 90'))||
((keyEntry> = ' 97')& &(keyEntry< = ' 122'))||
(keyEntry == ' 46')||
(keyEntry == ' 32')||
keyEntry == ' 45' ||
keyEntry == ' 46' ||
keyEntry == ' 8' ||
keyEntry == ' 35' ||
keyEntry == ' 36' ||
keyEntry == ' 9')
返回 true ;
else
return false < /跨度>;
}
并添加onkeydown&代码背后的onpaste处理程序
TextBox1.Attributes.Add(onkeydown,return handleKeydown(event));
TextBox1.Attributes.Add(onpaste,return handleKeydown(event));
希望这会对你有帮助。
touseef4pk写道:说我想限制为3个三个字符。它不仅应该输入少于或多于三个字符。
有很多方法:
1)使用Javascript - 编写文本框的代码onblur来检查长度是否等于3。
< asp:TextBox ID = TextBox1 runat = server onblur = javascript:validate( ); > < / asp:TextBox >
function validate()
{
if ( document .getElementById( TextBox1)。value.length!= 3 )
{
alert( text lenghth必须为3);
document .getElementById( TextBox1< /跨度>)选择();
document .getElementById( TextBox1< /跨度>)聚焦();
return false ;
}
其他
{
返回 真跨度>;
}
}
2)使用RegularExpressionValidator
。你需要写一个正则表达式来检查输入的值是3个字符。
touseef4pk写道:请告诉我如何编写reqular表达式来限制文本框中最多三个字符的字符
试试这个:\ b [a-zA-Z] {3} \b
[/编辑]
touseef4pk写道:我想只允许文本框中的文字。
文本是指字母数字,这是文本框的默认值。
我猜你不是那个意思。请澄清。
感谢您的回复。请告诉我如何编写reqular表达式来限制文本框中最多三个字符的字符。 Actualy我的意思是说输入shoule只是字母,只有The。它不应该接受数值。请帮我解决这个冲突。
Dear fellow,
How can I fix character length in textbox? Say i want to restrict to 3 three characters. It should not only to enter less than or more than three characters. And secondly, I want to allow only text in the textbox. Please help me out.
1.To restrict maxlength of textbox with three character, write
<asp:TextBox ID="TextBox1" runat="server" MaxLength="3"></asp:TextBox>
2.To match exactly three character in textbox add following javascript function
function checkLength(obj) { if (obj.value.length != 3) { alert("Should be exactly three char."); obj.focus(); } }
And call the function in onblur event
TextBox1.Attributes.Add("onblur", "checkLength(this)");
3.To allow only text in textbox add following javascript function
function handleKeydown(event) { keyEntry = event.keyCode || event.which; if ( ((keyEntry >= '65') && (keyEntry <= '90')) || ((keyEntry >= '97') && (keyEntry <= '122')) || (keyEntry == '46') || (keyEntry == '32') || keyEntry == '45' || keyEntry == '46' || keyEntry == '8' || keyEntry == '35' || keyEntry == '36'|| keyEntry == '9') return true; else return false; }
And add onkeydown & onpaste handler in code behind
TextBox1.Attributes.Add("onkeydown", "return handleKeydown(event)"); TextBox1.Attributes.Add("onpaste", "return handleKeydown(event)");
Hope this will help you.
touseef4pk wrote:Say i want to restrict to 3 three characters. It should not only to enter less than or more than three characters.
There are many ways:
1) Use Javascript - Write code onblur of the textbox to check if the length is equal to 3 or not.
<asp:TextBox ID="TextBox1" runat="server" onblur="javascript:validate();"></asp:TextBox>
function validate() { if(document.getElementById("TextBox1").value.length != 3) { alert("text lenghth must be three"); document.getElementById("TextBox1").select(); document.getElementById("TextBox1").focus(); return false; } else { return true; } }
2) UseRegularExpressionValidator
. You need to write a regular expression which checks the value entered is 3 characters.
[Edit]
touseef4pk wrote:Please tell me how can i write reqular expression to limit characters upto three characters in textbox
Try this: \b[a-zA-Z]{3}\b
[/Edit]
touseef4pk wrote:I want to allow only text in the textbox.
Text means alphanumeric which is the default for a textbox.
I guess you don't mean that. Please clarify.
Thanks for reply. Please tell me how can i write reqular expression to limit characters upto three characters in textbox. Actualy I mean to say that the input shoule be alphabetical only like "The". It should not accept numeric values. Please help me to resolve this conflict.
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