连接属性尚未在C#中初始化 [英] Connection property has not been initialized in C#
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问题描述
更新我的SQL服务器压缩数据库时发生错误(.sdf)
我正在使用C#windows窗体应用程序
这是错误
ExecuteNonQuery:连接属性尚未初始化。
这是我的更新代码
我在这里停留了3h是什么问题
提前感谢!
An error occurred when I update my SQL server compact database (.sdf)
I'm using C# windows form application
This is the error
ExecuteNonQuery: Connection property has not been initialized.
This is my update code
What is the wrong I stuck 3h in here
Thank in advance !
int index = cb1.SelectedIndex; //combo box
int uid=1;
SqlCeConnection con = new SqlCeConnection("Data Source="C:\application\application.sdf;Persist Security Info=False;");
con.Open();
SqlCeCommand cm = new SqlCeCommand("UPDATE tbl_user SET u_name=@u_name , u_scl=@u_scl , u_ext=@u_ext WHERE u_id=@u_id");
cm.Parameters.AddWithValue("@u_id", uid);
cm.Parameters.AddWithValue("@u_name", txtname.ToString());
cm.Parameters.AddWithValue("@u_scl", txtscl.ToString());
cm.Parameters.AddWithValue("@u_ext",index );
try
{
int eff = cm.ExecuteNonQuery();
if (eff == 1)
{
con.Close();
MessageBox.Show("User Added", "Done");
}
else
{
con.Close();
MessageBox.Show("not inserted ", "Error");
}
}
catch (SqlCeException ex)
{
MessageBox.Show(ex.ToString());
}
推荐答案
简单。你创建了一个SqlCeConnection对象和一个SqlCeCommand对象,但你从未告诉命令对象使用连接对象。
我认为你在寻找这个 [ ^ ]。
Easy. You made a SqlCeConnection object and a SqlCeCommand object, but you never told the command object to use the connection object.
I think you're looking for this[^].
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