An attempt was made to set a report parameter 'SubImgPath' that is not defined in this report?

Question

I have created a child report which loads data if a parameter is passed from Parent Report. It works fine except for the IMAGE. Image doesn't load. It fails by throwing error:

An attempt was made to set a report parameter 'SubImgPath' that is not defined in this report.

I have defined a parameter 'SubImgPath' inside Child Report and sending parameter but fails:

    ReportViewer1.LocalReport.EnableExternalImages = true;
    string FilePath = new Uri(Server.MapPath("~/SiteImages/")).AbsoluteUri;
    ReportParameter param = new ReportParameter("SubImgPath", FilePath);
    ReportViewer1.LocalReport.SetParameters(param);
    ReportViewer1.LocalReport.Refresh();

Answer 1

You need to define the parameter in your report.

In the designer you can use this command: CTRL+ALT+D to open the Report Data panel, or you can access it by the menu: View > Report Data

Here you can define the parameters for your report.

Here is in short how to pass down a report parameter:

• Goto SubReport > Report Data Pane > Parameters and add the parameter you want to receive.

• Goto MainReport > Right-click SubReport > Subreport Properties > Parameters and add the same parameter name and pick the relevant
  value from the dropdown.