Question

The path is javascript path

    var fileName = args.get_fileName();
    lstImg.src = <%=GetListImageFilePath(fileName) %>

file name is error because it is javascript and not in .NET
how to put this argument in .NET Code

Answer 1

You’ll need to use AJAX. One easy way to do it would be to use PageMethods. First, add a [WebMethod] attribute to your method:

[WebMethod]
protected static string GetListImageFilePath(string fileName)
{

This method must be static.

Then set EnablePageMethods="True" on your script manager. Then you can call your c# code from JavaScript like this:

var fileName = args.get_fileName();
PageMethods.GetListImageFilePath(fileName, function (path) {
    lstImg.src = path;
});