使用 DISTINCT 时如何将 <Select> 放入组合框中

Question

我试图在使用 DISTINCT is use 时放入组合框。

无需 DISTICNT 即可工作

<

using (SqlConnection conn = new SqlConnection(zGV.csAviation))
{
    try
    {
        string query = "select '<Select>' as name, 0 as id union Select name, id from Airlines ORDER BY Name ";

        SqlDataAdapter da = new SqlDataAdapter(query, conn);
        conn.Open();
        DataSet ds = new DataSet();
        da.Fill(ds, "airline");
        cbxAirline.DisplayMember = "Name";
        cbxAirline.ValueMember = "ID";

        cbxAirline.DataSource = ds.Tables["airline"].DefaultView;
    }
    catch (Exception ex)
    {
        // write exception info to log or anything else
        MessageBox.Show("Error occured in Airline!");
    }
}

Answer 1

您可以简单地将不同的值应用于您最终想要的“非 ui”数据。

string query = "select '<Select>' as name, 0 as id union Select DISTINCT name, id from Airlines ORDER BY Name ";