Problem in exporting data to chart

Hi,

I would like to make chart with taskname (on X-axis) and timetakenfortheTask (on y-axis).

in my database i have data as:
Taskname   timetakenfortheTask(hrs)
Writing         1:00
printing          2:30
delivery          5:00

I wrote code like this:

With the below code i am getting all task names on x-axis. But i am not getting "timetakenfortheTask" on y-axis with times.

chart1.Enabled = true;

con.Open();

chart1.DataSource = null;

SqlCommand chartcmd = new SqlCommand("select taskname, timetakenfortheTask from Time_sheet where Name='" + cmbEmpnam.Text + "';", con);

chartcmd.Connection = con;

SqlDataAdapter chartada = new SqlDataAdapter(chartcmd);

DataSet ds = new DataSet();

chartada.Fill(ds);

DataView source = new DataView(ds.Tables[0]);

chart1.DataSource = source;

chart1.Series[0].XValueMember = "taskname";

chart1.Series[0].YValueMembers = "timetakenfortheTask";

chart1.DataBind();

con.Close();

Advance thanks,

Darma