DataRow没有出现

Question

我使用了DataRow，它可以显示在WinForm中的组合框中，但不知怎么的，它不起作用，尽管整个表正在网格视图中成功显示。

   private void Form1_Load(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection();
        SqlCommand cmd = new SqlCommand();
        SqlDataAdapter da = new SqlDataAdapter();
        DataTable dt = new DataTable();
        DataSet ds = new DataSet();

        con.ConnectionString = "Data Source=.;Initial Catalog=StudentDetails;Integrated Security=True";
        cmd.Connection = con;
        cmd.CommandText = "select * from StuDet";
        da.SelectCommand = cmd;
        da.Fill(ds);

        dt = ds.Tables[0];
        dataGridView1.DataSource = dt;

        DataRow dr = dt.NewRow();
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            comboBox1.Items.Add(dr[0]);
        }
    }

Answer 1

刚才知道答案了，请看下面的循环。

   private void Form1_Load(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection();
        SqlCommand cmd = new SqlCommand();
        SqlDataAdapter da = new SqlDataAdapter();
        DataTable dt = new DataTable();
        DataSet ds = new DataSet();

        con.ConnectionString = "Data Source=.;Initial Catalog=StudentDetails;Integrated Security=True";
        cmd.Connection = con;
        cmd.CommandText = "select * from studet";
        da.SelectCommand = cmd;
        da.Fill(ds);

        dt = ds.Tables[0];
        dataGridView1.DataSource = dt;
 ////////////////////////////////////////////////////

        DataRow dr = dt.NewRow();
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            dr[0] = dt.Rows[i][0];
            comboBox1.Items.Add(dr[0]);
        }
    }

Answer 2

创建一个空的新行。

DataRow dr = dt.NewRow();

并将其添加到Rows.Count时间到comboBox1中。我想你想要的是检查dt.Rows中的每一行

foreach (DataRow dr in dt.Rows)
{
    comboBox1.Items.Add(dr["Roll"]);
}