ComboBox的SqlDataReader [英] SqlDataReader for ComboBox

问题描述

你好朋友，

我在下面有这个代码，应该从SQL DB列ubytov中选择项目。但它没有选择任何价值。为什么？

Hello friends,
I have got this code below which should select item from SQL DB column ubytov. But it doesn't select any value. Why?

try
           {
               SqlCommand novyprikaz = new SqlCommand("SELECT * FROM klient WHERE akce=" + vyberradek, spojeni);
               spojeni.Open();
               SqlDataReader precti = novyprikaz.ExecuteReader();

               if (precti.Read())
               { comboBox2.SelectedItem = precti.GetString(precti.GetOrdinal("ubytov"));
               }

           }
           catch (Exception ex)
           {
               MessageBox.Show("Chybové hlášení2: " + ex.Message.ToString());
           }

           spojeni.Close();
       }

这就是我在form_load上填写它的方式

And this is how I fill it on form_load

private void klient_Load(object sender, EventArgs e)
       {
           spojeni.Open();
           var cb1 = new SqlCommand("SELECT odjezd FROM stanice WHERE akce="
                            + vyberradek+ " ORDER BY odjezd ASC", spojeni);
           var cb2 = new SqlCommand("SELECT text FROM ubytov WHERE akce="
                           + vyberradek + " ORDER BY text ASC", spojeni);
           try
           {
               SqlDataReader dr = cb1.ExecuteReader();
               while (dr.Read())
               {
                   comboBox1.Items.Add(dr["odjezd"]);

               }
               dr.Close();
               dr.Dispose();
               SqlDataReader dr2 = cb2.ExecuteReader();
               while (dr2.Read())
               {
                   comboBox2.Items.Add(dr2["text"]);

               }
               dr2.Close();
               dr2.Dispose();

               spojeni.Close();
           }

任何人都知道我该怎么办？

Anyone know what should I do with it ?

推荐答案

建议始终使用参数化查询。显示如何填充组合框的示例（我假设klient是表名）。

Advised to use parameterized query always. Showing example how to fill combo box(I assume klient is table name).

SqlCommand novyprikaz = new SqlCommand("SELECT * FROM klient WHERE akce=@xyz", spojeni);
spojeni.Open();
cmd.Parameters.AddWithValue("xyz",your actual value);//like textbox text
SqlDataAdapter da = new SqlDataAdapter(novyprikaz);
DataSet ds = new DataSet();
da.Fill(ds);
comboBox2.DataSource=ds;
comboBox2.DataBind();

问候..：笑：

Regards.. :laugh:

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