C#读取Mysql blob字段-Mysql Tutorial-php.cn

C#读取Mysql blob字段

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Release： 2016-06-07 15:52:32

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开发环境：Windows XP Professional SP3、VS2008、Winform、MySQL5.0、MySQL.Data6.2.3.0 1、从硬盘上读取一图片，将其转化为流，然后存储到此BLOB字段中 view plaincopy to clipboardprint? private void button1_Click( object sender,EventArgse) { byte

开发环境：Windows XP Professional SP3、VS2008、Winform、MySQL5.0、MySQL.Data6.2.3.0

1、从硬盘上读取一图片，将其转化为流，然后存储到此BLOB字段中

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private void button1_Click(object sender, EventArgs e)
{
byte[] bytes = null;
bytes = File.ReadAllBytes(@"C:/Documents and Settings/user/My Documents/My Pictures/11.jpg");
using (MySql.Data.MySqlClient.MySqlConnection conn = new MySql.Data.MySqlClient.MySqlConnection())
{
conn.ConnectionString = ConfigurationManager.ConnectionStrings["test"].ConnectionString;
MySql.Data.MySqlClient.MySqlCommand cmd = new MySql.Data.MySqlClient.MySqlCommand();
cmd.CommandText = "insert into test(id,picture) values(@id,@picture)";
cmd.CommandType = CommandType.Text;
cmd.Parameters.Add("@id", MySql.Data.MySqlClient.MySqlDbType.Int32);
cmd.Parameters.Add("@picture", MySql.Data.MySqlClient.MySqlDbType.Blob);
cmd.Parameters[0].Value = 15;
cmd.Parameters[1].Value = bytes;
cmd.Connection = conn;
conn.Open();
int affectedrows = cmd.ExecuteNonQuery();
cmd.Dispose();
conn.Close();
}
}

private void button1_Click(object sender, EventArgs e)
        {
            byte[] bytes = null;
            bytes = File.ReadAllBytes(@"C:/Documents and Settings/user/My Documents/My Pictures/11.jpg");
            using (MySql.Data.MySqlClient.MySqlConnection conn = new MySql.Data.MySqlClient.MySqlConnection())
            {
                conn.ConnectionString = ConfigurationManager.ConnectionStrings["test"].ConnectionString;
                MySql.Data.MySqlClient.MySqlCommand cmd = new MySql.Data.MySqlClient.MySqlCommand();
                cmd.CommandText = "insert into test(id,picture) values(@id,@picture)";
                cmd.CommandType = CommandType.Text;
                cmd.Parameters.Add("@id", MySql.Data.MySqlClient.MySqlDbType.Int32);
                cmd.Parameters.Add("@picture", MySql.Data.MySqlClient.MySqlDbType.Blob);

cmd.Parameters[0].Value = 15;
                cmd.Parameters[1].Value = bytes;
                cmd.Connection = conn;
                conn.Open();

int affectedrows = cmd.ExecuteNonQuery();

cmd.Dispose();
                conn.Close();
            }

}

2、读取此BLOB字段，将其转化为图片显示在Picturebox控件上

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private void button2_Click(object sender, EventArgs e)
{
using (MySql.Data.MySqlClient.MySqlConnection conn = new MySql.Data.MySqlClient.MySqlConnection())
{
conn.ConnectionString = ConfigurationManager.ConnectionStrings["test"].ConnectionString;
conn.Open();
MySql.Data.MySqlClient.MySqlCommand cmd = new MySql.Data.MySqlClient.MySqlCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "select id,picture from test where id = 11";
cmd.Connection = conn;
System.Data.Common.DbDataReader reader = cmd.ExecuteReader();
byte[] buffer = null;
if (reader.HasRows)
{
reader.Read();
long len = reader.GetBytes(1, 0, null, 0, 0);//1是picture
buffer = new byte[len];
len = reader.GetBytes(1, 0, buffer, 0, (int)len);
System.IO.MemoryStream ms = new System.IO.MemoryStream(buffer);
System.Drawing.Image iamge = System.Drawing.Image.FromStream(ms);
pictureBox1.Image = iamge;
}
}
}

private void button2_Click(object sender, EventArgs e)
        {
            using (MySql.Data.MySqlClient.MySqlConnection conn = new MySql.Data.MySqlClient.MySqlConnection())
            {
                conn.ConnectionString = ConfigurationManager.ConnectionStrings["test"].ConnectionString;
                conn.Open();

MySql.Data.MySqlClient.MySqlCommand cmd = new MySql.Data.MySqlClient.MySqlCommand();
                cmd.CommandType = CommandType.Text;
                cmd.CommandText = "select id,picture from test where id = 11";
                cmd.Connection = conn;

System.Data.Common.DbDataReader reader = cmd.ExecuteReader();
                byte[] buffer = null;
                if (reader.HasRows)
                {
                    reader.Read();
                    long len = reader.GetBytes(1, 0, null, 0, 0);//1是picture
                    buffer = new byte[len];
                    len = reader.GetBytes(1, 0, buffer, 0, (int)len);

System.IO.MemoryStream ms = new System.IO.MemoryStream(buffer);
                    System.Drawing.Image iamge = System.Drawing.Image.FromStream(ms);
                    pictureBox1.Image = iamge;
                }
            }

}

数据库相关文件配置在App.config中，如果不用配置文件，可以写成：

string remote = "Persist Security Info=False;database=lhwtouch;server=服务器IP;user id=用户名;pwd=密码";

然后conn.ConnectionString = remote;即可。

后记：

之前在.net中用的mysql库是：MySQLDriverCS，但是一直没有搞定，而且用官方给的读取blob字段也失败。于是改用MySql.Data，注意Mysql.Data5.0版本不支持读取Blob字段，所以需要用较高版本，我用的是MySQL.Data6.2.3.0。

MySql.Data6.2.3.0下载地址：http://download.csdn.net/source/2968152

MySql.Data5.0.9.0下载地址：http://download.csdn.net/source/2968157

代码提供者：http://hi.csdn.net/Dobzhansky，在此深表感谢！

http://blog.csdn.net/config_man/article/details/6123191