为什么总是提示：Connection must be valid and open？高分赠送。

[zht1009]

在C#访问MySql时，执行到这个方法时总是提示：Connection must be valid and open.
public int RecordCount(string sqlWhere)
{
string strSQL = "Select Count(*) From province Where 1 = 1" + sqlWhere;
object o = MySqlHelper.ExecuteScalar(strSQL);

if (o != null) return Convert.ToInt32(o);
else return 0;

}

以下是MySqlHelper.ExecuteScalar():
public static object ExecuteScalar(string cmdText)
{
MySqlConnection conn = new MySqlConnection(DBConnectionString);
MySqlCommand cmd = new MySqlCommand(cmdText,conn);

object o = cmd.ExecuteScalar();
return o;

}

同志们帮忙分析一下，多谢。

[q107770540]

public static object ExecuteScalar(string cmdText)
{
MySqlConnection conn = new MySqlConnection(DBConnectionString);
MySqlCommand cmd = new MySqlCommand(cmdText,conn);
//你的 conn 都木有open 啊
object o = cmd.ExecuteScalar();
return o;

}

[阿非]

MySqlConnection conn = new MySqlConnection(DBConnectionString);
=>
MySqlConnection conn = new MySqlConnection(DBConnectionString);
conn.Open();

----------
object o = cmd.ExecuteScalar();
=>
object o = cmd.ExecuteScalar();
conn.Close();

[q107770540]

下载最新的 下载mysql-connector-net
连接字符串中注意 server端口号要正确

[hztltgg]

Connection must be valid and open？
连接　　　　必须　是　有效的　和　打开的？

[xiaozhang1528008]

[Quote=引用 4 楼 hztltgg 的回复:]
Connection must be valid and open？
连接　　　　必须　是　有效的　和　打开的？
[/Quote]
+1

[三石-gary]

[Quote=引用 1 楼 q107770540 的回复:]

public static object ExecuteScalar(string cmdText)
{
MySqlConnection conn = new MySqlConnection(DBConnectionString);
MySqlCommand cmd = new MySqlCommand(cmdText,conn);
//你的 conn 都木有open ……
[/Quote]
+1

[jdc71264]

大哥，在调用command对象的方法时，con必须是open的啊

[success1000]

public static object ExecuteScalar(string cmdText)
{
MySqlConnection conn = new MySqlConnection(DBConnectionString);
conn.Open();
MySqlCommand cmd = new MySqlCommand(cmdText,conn);

object o = cmd.ExecuteScalar();
conn.Close();
return o;

}

[阿非]

你还敢再倒的明目张胆点么?