I\'m trying to use asp:
I want a way to spe
MaxLength is now supported as of .NET 4.7.2, so as long as you upgrade your project to .NET 4.7.2 or above, it will work automatically.
You can see this in the release notes here - specifically:
Enable ASP.NET developers to specify MaxLength attribute for Multiline asp:TextBox. [449020, System.Web.dll, Bug]