C# Access Db 更新查询不起作用

Question

我正在尝试使用下面提到的代码更新 Access 表。但是，更新不会执行。它不会给我任何错误，但不会更新数据库。有什么建议吗？

string Const = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=F:\\Db\\test.accdb";      

OleDbCommand Cmd;
OleDbConnection con22 = new OleDbConnection(Const );
con22.Open();

string sql = "UPDATE CostT SET tFormSent='" + Selection1.Text + "',TName='" + UserName.Text + "',FormDate='" + FormDate.Text + "',where ReqNum=" + ReqNum.Text;

cmd = new OleDbCommand(sql, con22);
cmd.ExecuteNonQuery();
con22.Close();

MessageBox.Show("Form has been Updated");

Answer 1

尝试更改查询
到

string sql = "UPDATE CostT SET tFormSent = @selection1,TName = @UserName,FormDate = @FormDate where ReqNum = @ReqNum";
cmd = new OleDbCommand(sql, con22);
cmd.Parameters.Add("@selection1", Selection1.Text);
cmd.Parameters.Add("@UserName", UserName.Text);
cmd.Parameters.Add("@FromDate", FromDate.Text);
cmd.Parameters.Add("@ReqNum", ReqNum.Text);
cmd.ExecuteNonQuery();
con22.Close();