maxlength on multiline textbox. Discussion in Microsoft ASP .NET started by hardcoded, May 5, 2004.This maxlength value seems to get ignored as the user can enter unlimited characters. Does the multiline textbox not support maxlength? I have to control the length of the message to be sent But for textbox of Multiline type did not allowing the MaxLength property So plz do favour for me regarding this one.asp:TextBox runat"server" ID"MLTextBox". TextMode"MultiLine" > ).prop( maxlength, 20) . Yeah, its a bit hacky, but if you want to use the asp control (I didnt want to have to deploy a code change), it works. Read CSV File Using C ASP.Net. Staying Late Office.