c# 开发 mysql 乱码

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今天用C#类连接mysql数据库出现中文乱码具体解决方案如下：

用到的mysql表结构：

CREATE TABLE IF NOT EXISTS `tet` (
`id` int(11) NOT NULL,
`name` varchar(255) NOT NULL,
`url` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

用到的mysql表数据：

INSERT INTO `tet` (`id`, `name`, `url`) VALUES
(1, '百度 ', 'http://www.baidu.com '),
(0, 'google ', 'http://www.google.com.hk '),
(3, '400电话 ', 'http://www.my400800.cn ');

一、查询结果没有问题，在查询条件中如果输入中文查询不到内容，用insert测试为，插入的内容是乱码

首先在MySQL Command Line Client里面输入“SHOW VARIABLES LIKE 'character_set_%';”，可看到如下字符：

Variable_name	Value
character_set_client	utf8
character_set_connection	utf8
character_set_database	utf8
character_set_filesystem	binary
character_set_results	utf8
character_set_server	latin1
character_set_system	utf8
character_sets_dir	C:\Program Files\VertrigoServ\Mysql\share\charsets\

可以用如下连接字符串解决中文乱码问题

User Id=test;Host=localhost;Database=eczhou;password=test;charset='gb2312'

二、检索结果和插入内容都是乱码

用MySQL Command Line Client里面输入“SHOW VARIABLES LIKE 'character_set_%';”，可看到如下字符：

Variable_name	Value
character_set_client	utf8
character_set_connection	utf8
character_set_database	utf8
character_set_filesystem	binary
character_set_results	utf8
character_set_server	utf8
character_set_system	utf8
character_sets_dir	/usr/share/mysql/charsets/

即便是连接字符串改成

User Id=test;Host=localhost;Database=eczhou;password=test;charset=utf8 检索的结果还是乱码

郁闷中。。。。。。。

然后用 show variables like 'collation%';显示结果是：

+----------------------+-----------------+
| Variable_name | Value |
+----------------------+-----------------+
| collation_connection | utf8_general_ci |
| collation_database | utf8_general_ci |
| collation_server | utf8_general_ci |
+----------------------+-----------------+

show variables like 'character%';

+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | latin1 |
| character_set_connection | latin1 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | latin1 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+

经过不懈努力的查找，终于找到问题了,问题就出在上面红色字体的编码上，我的解决方法如下：

连接字符串修改如下：

server=localhost;uid=root;pwd=root;database=test;Charset=latin1

c#代码如下：

/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataSet</returns>
public static DataSet Query(string SQLString)
{
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
DataSet ds = new DataSet();

try
{
connection.Open();
MySqlCommand M = new MySqlCommand("set names 'latin1'", connection);
M.ExecuteNonQuery();
//

MySqlDataAdapter da = new MySqlDataAdapter(SQLString, connection);
da.Fill(ds);
}
catch (MySqlException ex)
{
connection.Close();
throw new Exception(ex.Message);
}
finally
{
connection.Close();
}
DataTable dt = ds.Tables[0];
foreach (DataRow dr in dt.Rows)
{
for (int i = 0; i < dt.Columns.Count; i++)
{
dr[i] = Encoding.UTF8.GetString(Encoding.GetEncoding("latin1").GetBytes(dr[i].ToString()));
}


}

return ds;
}
}

一定要注意上面的红色字体。

http://www.linuxso.com/php/16911.html