windows 如何在 MySQL 数据库 longblob 中检索图像？
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how to retrieve image in MySQL database longblob?
提问by Sagotharan
I am using Windows Form and MySQL for my project. In that i want to save a image and retrieve that.
我在我的项目中使用 Windows 窗体和 MySQL。因为我想保存图像并检索它。
I have created a table named 'image' in that,
我在其中创建了一个名为“image”的表，
CREATE TABLE `image` (
`id` INT(15) NOT NULL AUTO_INCREMENT,
`extension` VARCHAR(50) NOT NULL,
`image` LONGBLOB NOT NULL,
PRIMARY KEY (`id`)
)
ENGINE=MyISAM
ROW_FORMAT=DEFAULT
AUTO_INCREMENT=2
And
和
OpenFileDialog open = new OpenFileDialog();
// image filters
open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp; *.png)|*.jpg; *.jpeg; *.gif; *.bmp; *.png";
if (open.ShowDialog() == DialogResult.OK)
{
txt_imagePath.Text = open.FileName;
}
hp.getConnStr();
try
{
MySqlConnection connection = new MySqlConnection(hp.myConnStr);
MySqlCommand command = connection.CreateCommand();
command.CommandText = "insert into image (image) values ('"+txt_imagePath.Text +"')";
command.Connection.Open();
command.ExecuteNonQuery();
command.Connection.Close();
}
in Browse button click event,..
在浏览按钮点击事件中，..
The file is successfully saved. Now i want to retrieve that picture and show in picture box. So that i try this bellow code,..
文件已成功保存。现在我想检索该图片并显示在图片框中。所以我尝试这个波纹管代码，..
MySqlConnection connection = new MySqlConnection(hp.myConnStr);
MySqlCommand command = connection.CreateCommand();
MySqlDataReader Reader;
command.CommandText = "select image from image";
connection.Open();
Reader = command.ExecuteReader();
while (Reader.Read())
{
pictureBox1.Image = new Bitmap(Reader[0].ToString());
}
connection.Close();
but no use.
但没有用。
Please help me.
请帮我。
采纳答案by Emir Akayd?n
You should read the blob field as a MemoryStreamand set to Imageproperty of the control using Image.FromStream().
您应该将 blob 字段读取为 aMemoryStream并使用 设置为Image控件的属性Image.FromStream()。
回答by Sudhir Bastakoti
I hope something like this would help:
我希望这样的事情会有所帮助：
public Bitmap loadImage(int imgID)
{
MySqlDataReader myData;
MySqlCommand cmd = new MySqlCommand();
string SQL;
byte[] rawData;
MemoryStream ms;
UInt32 FileSize;
Bitmap outImage;
SQL = "SELECT ImageName, ImageSize, Image FROM Images WHERE ImageID =";
SQL += imgID.ToString();
try
{
cmd.Connection = connection;
cmd.CommandText = SQL;
myData = cmd.ExecuteReader();
if (!myData.HasRows)
throw new Exception("There are no blobs to save");
myData.Read();
FileSize = myData.GetUInt32(myData.GetOrdinal("ImageSize"));
rawData = new byte[FileSize];
myData.GetBytes(myData.GetOrdinal("Image"), 0, rawData, 0, (Int32)FileSize);
ms = new MemoryStream(rawData);
outImage = new Bitmap(ms);
ms.Close();
ms.Dispose();
myData.Close();
myData.Dispose();
cmd.Dispose();
return outImage;
}
catch (MySqlException ex)
{
MessageBox.Show(ex.Message);
return null;
}
}
回答by Vladislav Vaintroub
while (Reader.Read())
{
pictureBox1.Image = new Bitmap(new MemoryStream((byte[])Reader.GetValue(0)));
}
this should do it. reader.GetValue() returns byte array on MySQL blobs, this does the trick.
这应该这样做。reader.GetValue() 在 MySQL blob 上返回字节数组，这就是诀窍。
