You need to create a parameter in report and pass the value to it at runtime in your code. This parameter can be set to display the assigned value during report viewing.
Something like:
List<ReportParameter> paramList = new List<ReportParameter>();
paramList.Add(new ReportParameter("SurnameColumnHeader",
GetGlobalResourceObject("UserReport", "SurnameColumn").ToString()));
ReportViewer1.LocalReport.SetParameters(paramList);
Following resource should help:
Setting SSRS Report Parameters from ASP.NET C# Code[
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