ASP.NET TextBox.MultiLine maxlength Problem Solution

Solution Number 1 for

ASP.NET TextBox.MultiLine maxlength

Add following javascript

function Count(text,long)

{

      var maxlength = new Number(long); // Change number to your max length.

 

if(document.getElementById('<%=textBox.ClientID%>').value.length > maxlength){

 

            text.value = text.value.substring(0,maxlength);

 

            alert(" Only " + long + " chars");

 

}

Where “textBox” is the asp text box ID.
Also add following events in your textbox.

onKeyUp="javascript:Count(this,200);" onChange="javascript:Count(this,200);"

Your textbox code should look like

 

<asp:TextBox ID="textBox" onKeyUp="javascript:Count(this,2);" onChange="javascript:Count(this,2);"  TextMode=MultiLine Columns="5" Rows="5" runat=server>

    </asp:TextBox>

 
Solution Number 2 for

ASP.NET TextBox.MultiLine maxlength

Another way to achieve this is regular expression. You can add following regular expression validate on asp text box.

<asp:RegularExpressionValidator ID="txtConclusionValidator1" ControlToValidate="textBox" Text="Exceeding 200 characters" ValidationExpression="^[\s\S]{0,2}$" runat="server" />

Solution Number 2 for

ASP.NET TextBox.MultiLine maxlength

 

http://www.codeproject.com/KB/aspnet/Textarea_Length_Validator.aspx

Selt Define Control: