call delete if not exists condition in c#

Alter proc usp_DelTechnology
(
   @TechnologyID int
)

AS

BEGIN
 -- make sure we don't have reference descriptions
if(NOT EXISTS(select TechnologyID from tblTechnologySubTypes where TechnologyID = @TechnologyID) and
   NOT EXISTS(select TechnologyID from tblApplicationVsTechnologies where TechnologyID = @TechnologyID) and
   NOT EXISTS(select TechnologyID from tblEffortHours where TechnologyID = @TechnologyID))
BEGIN
 DELETE from tblTechnologies where TechnologyID = @TechnologyID
 RETURN 1
END
   ELSE
     BEGIN
       Return 0
     END
END

private void ImageButton_Click(object sender, EventArgs e)
{
    using (SqlConnection con = new SqlConnection("Your database connection string here."))
    {
        using (SqlCommand cmd = new SqlCommand("usp_DelTechnology", con))
        {
           cmd.CommandType = CommandType.StoredProcedure;
           cmd.Parameters.Add("@TechnologyID", SqlDbType.int).Value = GridView1.Cells[0].Text; //access technology Id from Gridview
           con.Open();
           int returnValue = cmd.ExecuteNonQuery();
           if (returnvalue == 0)
           {
               //Display message - There are references
           }
           else
           {
               //Deleted Successfully message.
           }

        }
    }
}