Bind sql data source to dropdownlist

Question

private void fillExamList()

{

string selectExamination = "SELECT ExamCode, ExamType + ', ' + ExamDate AS ExamList FROM Examination WHERE PatientID = " + txtSearchID.Text + "";

SqlDataAdapter da = new SqlDataAdapter(selectExamination, conn);

DataSet ds = new DataSet();

try

{

conn.Open();

da.Fill(ds);

foreach (DataRow dr in ds.Tables["Table"].Rows)

{

if (dr["ExamType"].ToString() == "0")

{

dr["ExamType"] = "Yes";

}

}

ddlExamList.DataValueField = "ExamCode";

ddlExamList.DataTextField = "ExamList";

ddlExamList.DataSource = ds;

ddlExamList.DataBind();

ddlExamList.Items.Insert(0, new ListItem("Select...", "0"));

}

catch (Exception ex)

{

ErrorHandling(ex.ToString());

}

finally

{

conn.Close();

}

}

 

When I run this code I get an error that says:

 

System.ArgumentException: Column 'ExamType' does not belong to table Table.

at System.Data.DataRow.GetDataColumn(String columnName)

at System.Data.DataRow.get_Item(String columnName)

at BindData.Default.fillExamList() in C:\Users\Ron\Documents\Visual Studio 2017\Projects\BindData\BindData\Default.aspx.cs:line xxx

 

How can I fix it?