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[英]SQL Delete Statement does not work with selecting a row from a dataGridView
[英]SQL connection selecting row to delete
我在 Visual Studio 中有一個本地數據庫,在我的項目中,我想刪除在 WPF 中選擇的行。
這是我到目前為止所得到的:
private void Delete(object sender, RoutedEventArgs e)
{
DataRowView o = (DataRowView)g2.SelectedItem;
int ID = Convert.ToInt32(o.Row.ItemArray[0]);
SqlConnection con = new SqlConnection();
con.ConnectionString = "Data Source=(LocalDB)\\MSSQLLocalDB;AttachDbFilename=MYFOLDER";
con.Open();
SqlCommand cmd = new SqlCommand();
cmd = new SqlCommand("DELETE FROM [STOCK] WHERE o = @ID", con);
cmd.Connection = con;
cmd.ExecuteNonQuery();
{
MessageBox.Show("Row deleted");
}
在這個語句中,我可以 select 一行:
DataRowView o = (DataRowView)g2.SelectedItem; int ID = Convert.ToInt32(o.Row.ItemArray[0]);
但后來我必須從我的本地數據庫中刪除它,我不知道如何完成這個。 我知道這句話是錯誤的……但正確的是什么: cmd = new SqlCommand("DELETE FROM [STOCK] WHERE o = @ID", con);
希望有人可以幫助我。 我正在使用 Visual Studio 2019 - 這是一個 WPF 項目,帶有 C#。
問候!
您需要參考DELETE
中的ID
列
另請注意以下事項
AttachDbFilename
是個壞主意,而是使用FOR ATTACH
正常附加數據庫using
處理連接和命令等對象try
catch
處理錯誤private void Delete(object sender, RoutedEventArgs e)
{
DataRowView o = (DataRowView)g2.SelectedItem;
int ID = Convert.ToInt32(o.Row.ItemArray[0]);
try
{
const string query = @"
DELETE FROM [STOCK] WHERE [STOCK].Id = @ID;
";
using (SqlConnection con = new SqlConnection(Properties.ConnectionString))
using (SqlCommand cmd = new SqlCommand(query, con))
{
cmd.Parameters.Add("@ID", SqlDbType.Int).Value = ID;
con.Open();
cmd.ExecuteNonQuery();
}
MessageBox.Show("Row deleted");
}
catch(Exception ex)
{
MessageBox.Show("Error occurred:\r\n" + ex.Message);
}
}
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