Crystal Report .mdf file "Failed to open the connection"

Question

I'm creating an application with multiple .mdf User can navigate in different database. Changing connection in my application is working fine. But when i try to use my connection in Crystal Report, error comes out ReportError

EDIT: Is there a way without running the sp_attach_db

public static void Show(ReportDocument reportDocument, string reportFileName)
{
  try
  {
    ReportViewer reportViewer = new ReportViewer();
    CrystalDecisions.CrystalReports.Engine.ReportObjects crReportObjects;
    CrystalDecisions.CrystalReports.Engine.SubreportObject crSubreportObject;
    CrystalDecisions.CrystalReports.Engine.ReportDocument crSubreportDocument;
    CrystalDecisions.CrystalReports.Engine.Database crDatabase;
    CrystalDecisions.CrystalReports.Engine.Tables crTables;
    TableLogOnInfo crTableLogOnInfo;

    CrystalDecisions.Shared.ConnectionInfo crConnectioninfo = new CrystalDecisions.Shared.ConnectionInfo();

    crConnectioninfo.ServerName = @".\SQLExpress";
    crConnectioninfo.DatabaseName = @"C:\Database\MyDatabase.mdf";
    crConnectioninfo.IntegratedSecurity = true;
    crDatabase = reportDocument.Database;
    crTables = crDatabase.Tables;

    foreach (CrystalDecisions.CrystalReports.Engine.Table crTable in crTables)
    {
      crTableLogOnInfo = crTable.LogOnInfo;
      crTableLogOnInfo.ConnectionInfo = crConnectioninfo;
      crTable.ApplyLogOnInfo(crTableLogOnInfo);
    }

    CrystalDecisions.CrystalReports.Engine.Sections crSections = reportDocument.ReportDefinition.Sections;
    foreach (CrystalDecisions.CrystalReports.Engine.Section crSection in crSections)
    {
      crReportObjects = crSection.ReportObjects;
      foreach (CrystalDecisions.CrystalReports.Engine.ReportObject crReportObject in crReportObjects)
      {
        if (crReportObject.Kind == ReportObjectKind.SubreportObject)
        {
          crSubreportObject = (CrystalDecisions.CrystalReports.Engine.SubreportObject)crReportObject;
          crSubreportDocument = crSubreportObject.OpenSubreport(crSubreportObject.SubreportName);
          crDatabase = crSubreportDocument.Database;
          crTables = crDatabase.Tables;

          foreach (CrystalDecisions.CrystalReports.Engine.Table crTable in crTables)
          {
            crConnectioninfo.ServerName = @".\SQLExpress";
            crConnectioninfo.DatabaseName = @"C:\Database\MyDatabase.mdf";
            crConnectioninfo.IntegratedSecurity = true;
            crTableLogOnInfo = crTable.LogOnInfo;
            crTableLogOnInfo.ConnectionInfo = crConnectioninfo;
            crTable.ApplyLogOnInfo(crTableLogOnInfo);
          }
        }
      }
    }

    reportViewer.RptDocument = reportDocument;
    reportViewer.RptDocument.ExportToDisk(ExportFormatType.PortableDocFormat, reportFileName);
    reportViewer.ReportFileName = reportFileName;
    reportViewer.Show();
  }
  catch (Exception ex)
  {
    MessageBox.Show(ex.Message, "Error in Loading Report", MessageBoxButtons.OK, MessageBoxIcon.Error);
  }
}