The report parameter 'param1' is read-only and cannot be modified. (rsReadOnlyReportParameter)

Question

hey guys..
I'm trying to get the report that I need to be filtered by a parameter value (named Param1)
I created a parameter in the data tab and tried to pass a value from my Web application to the report services.. now my report have that textbox that prompts me to enter the filtering value for the report I want.. everything works fine till this point..
now I have another webpage that has a report viewer and a textbox for the user input the value they want.. and pass it to the report.. and I'm using the following code to pass the value to the report I made earlier..
Dim par(0) As Microsoft.Reporting.WebForms.ReportParameter
par(0) = New Microsoft.Reporting.WebForms.ReportParameter("paramSiteCode", TextBox1.Text.ToString)
ReportViewer1.ServerReport.SetParameters(par)
ReportViewer1.ServerReport.Refresh()
however.. now I'm getting an error.. "The report parameter 'paramSiteCode' is read-only and cannot be modified. (rsReadOnlyReportParameter)"
what am I missing here? I've been thru the help and forums.. and the code should work.. or so I hope it would.. thanks in advance..

Answer 1

Details
Product:
sql server reporting services
ID:
rsreadonlyreportparameter
Source:
microsoft.reportingservices.diagnostics.utilities.errorstrings.resources.strings
Version:
8.00
Message:
The report parameter '{0}' is read-only and cannot be modified.
Explanation
This error occurs when you attempt to set a value for a parameter that is read-only. A parameter is read-only when the
Prompt property for the parameter is set to false.
User Action
To set a value for a parameter, the Prompt property for the parameter must be set to
true. You can set this property in two ways:
Before publishing the report, provide a prompt string for the parameter. In Report Designer, you can provide a prompt by typing a prompt string in the
Prompt text box in the Report Parameters dialog box.
After publishing the report, set the Prompt User property for the parameter. In Report Manager, in report properties, click the
Parameters tab, and then select Prompt User for the parameter.
For more information about report parameters in Report Designer and Report Manager, see Books Online.
In the release version of SQL Server 2000 Reporting Services, when Prompt is
true and Prompt String is blank, the parameter is still available to the user in the report viewer. In SP1, when
Prompt is true and Prompt String is blank, the parameter is hidden from the user.
Note: Publishing a report over an existing report on the report server does not overwrite the parameter information. To update parameters for an existing report, either delete the report on the report server and republish, or update the parameter information
for the report in Report Manager.
I struggled with the same problem in VS 2010.
After a long series of hoops to jump through, I modified the rdlc file by hand and added <Prompt>true</prompt>. This parameter cannot be set through the GUI - go figure.
In my case, I was attempting to generate a sub report, and pass a parameter to the sub report.
To get this to work, the sub report needed these two sections.
<ReportParameters>
<ReportParameter Name="Network_Id">
<DataType>String</DataType>
<Prompt>true</Prompt>
</ReportParameter>
</ReportParameters>
<Variables>
<Variable Name="Network_ID">
<Value />
</Variable>
</Variables>
I was then able to use the name "Network_Id" in the sub-report properties of the "sub report control" for the name of a parameter on the parameters tab. I then set it to the key value that I need in the subreport properties dialog.
Prior to setting prompt to true, I kept getting the read-only exception.
I'm not sure if I am being clear about this, but sub reports do work, and prompt can be manually added to the report definition file.