用c#编码从mysql表填充数据的问题 [英] problem with c# coding to populate data from mysql table
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问题描述
我用按钮制作一个文本框,以便在单击按钮时可以在该文本框中提供指定列的总和,必须在c#.plz帮助中完成
i m making a textbox with a button so that when button is clicked it gives sum of specified column in that textbox it has to be done in c#.plz help
MySqlConnection MyCon = new MySqlConnection("server=localhost; Database = nikz; user id=root; password=***; pooling=false;");
MyCon.Open();
MySqlCommand command = new MySqlCommand();
string SQL = "select sum(Actual_amt) from tds";
command.Connection = MyCon;
command.CommandText = SQL;
actamttxtbox.Text = SQL.ExecuteScalar();
command.ExecuteNonQuery();
MyCon.Close();
这就是我所做的,并且给出了错误
this is what i hav done and is giving errors
推荐答案
变量SQL
是一个字符串.string
没有方法ExecuteScalar()
改变
variableSQL
is a string. Astring
has no methodExecuteScalar()
change
actamttxtbox.Text = SQL.ExecuteScalar();
到
to
actamttxtbox.Text = (string)command.ExecuteScalar();
而且您不需要cmd.ExecuteNonQuery();
我已经整理了一下:
And you don''t need cmd.ExecuteNonQuery();
I''ve cleaned up a little bit:
MySqlConnection conn = new MySqlConnection("connection-string");
conn.Open();
using(MySqlCommand cmd = new MySqlCommand()){
cmd.Connection = conn;
cmd.CommandText = "select sum(Actual_amt) from tds";
actamttxtbox.Text = cmd.ExecuteScalar().ToString();
}
conn.Close();
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