Pass variable to SSRS report as parameter

Question

I have 2 winforms The first has a button that opens the second with a reportviewer that opens an SSRS report with a single parameter (CaseNo). I want to be able to pass the CaseNo from C# to the SSRS report.

This is what I currently have but I am not sure how to modify it to pass the parameter to the report.

private void btnOpenSummary_Click(object sender, EventArgs e)
{
    CaseSummRpt summRpt = new CaseSummRpt("Case_Summary", " / Security", lblCaseNo.Text);
    summRpt.ShowDialog();
}

Report Viewer Form

public CaseSummRpt(string rptText, string rptFolder, string CaseNo)
{
    InitializeComponent();
    string rptName;
    rptName = rptFolder + "/" + rptText;
    reportViewer1.ServerReport.ReportServerUrl = new Uri("http://servername:8000/servername_server");
    reportViewer1.ServerReport.ReportPath = rptName;
}