title: The type 'System.Data.SqlClient.SqlDataReader' has no constructors defined
body: <p>I have issues with SqlDataReader. I get the error "The type 'System.Data.SqlClient.SqlDataReader' has no constructors defined" when I try running the page. My intention here is to return a string value 0 if the user has not had access or 1 when the user has assess. Below is my code snippet.</p>
  
  <pre><code>public string CheckAssess(string emailAddress, string columnName)
  {
      string chkAssess;
      SqlDataReader readAssess;
      readAssess = new SqlDataReader();
  
      string MgrAssessQry = "SELECT '"+columnName+"' FROM tblAllUsers";
      MgrAssessQry += " WHERE email ='" + emailAddress + "'";
  
      SqlCommand cmdReadAssess = new SqlCommand(MgrAssessQry, cn);
      cn.Open();
      readAssess = cmdReadAssess.ExecuteReader();
  
      while(readAssess.Read())
      {
          // Add the rows
         chkAssess = readAssess["IsAssessMgr"].ToString();
      }
  
      return chkAssess;
  }
  </code></pre>