关于传参
现在我有个dropdownlist控件，我想通过传参的方法整合一下，但是以前没有接触过这个，希望大家能帮我看下哦

下面是dropdownlist控件数据绑定
protected void ddlGroupIDBind()
{
string sqlSel = "select GroupID,G_CName from sys_Group where G_ParentID !=0 order by GroupID ";
SqlConnection con = new SqlConnection(strCon); ;
con.Open();
SqlDataAdapter sda = new SqlDataAdapter(sqlSel, con);
DataSet ds = new DataSet();
sda.Fill(ds);
ddlGroupID.DataSource = ds.Tables[0].DefaultView;
ddlGroupID.DataTextField = "G_CName";
ddlGroupID.DataValueField = "GroupID";
ddlGroupID.DataBind();
}


下面是我写的传参


#region sys_UserPermission传参
public static string GetUserPermissionTable(string strTableUserPermission, int intID)
{
string dataset = "";
string sql = "select GroupID,G_CName from sys_Group where G_ParentID !=0 order by GroupID ";
using (SqlDataReader dr = DBhelper.ExecuteDataReader(System.Data.CommandType.Text, sql, null))
{
if (dr.HasRows)
{
while (dr.Read())
{

DataSet ds = new DataSet();
}
}
}
return dataset;
}

private static sys_UserPermission LoadUserPermissionTable(SqlDataReader dr)
{
sys_UserPermission UP = new sys_UserPermission();
UP.GroupID = DBhelper.ExecToInt32(dr,"GroupID");
UP.G_CName = DBhelper.ExecToString(dr,"G_CName");
return UP;
}

public static sys_UserPermission GetUserPermissionTableByName(int ID)
{
sys_UserPermission UP = new sys_UserPermission();
string sql = "";
using (SqlDataReader dr = DBhelper.ExecuteDataReader(System.Data.CommandType.Text, sql, new SqlParameter("@ID", ID)))
{
if (dr.HasRows)
{
if (dr.Read())
{
UP = LoadUserPermissionTable(dr);
}

}
}
return UP;
}
#endregion

传参我想获取的ds的值，但是貌似写的不对，希望大家能帮我看下怎么改哦。还有我写好后，后台要怎么才能调取这个方法
[解决办法]
public static string GetUserPermissionTable(string strTableUserPermission, int intID)
里面的 while (dr.Read())
{
DataSet ds = new DataSet();
}
什么都没做，返回一个空字符串？