如何将图像插入到Microsoft Access数据库？

Question

我试图转换图像插入到C＃.Net Windows窗体中的Microsoft Access数据库。 而且我想删除和改变图像。 但我不知道该怎么做。 请为我写一段代码。

Answer 1

我会将图像转换为一个字节[]和。然后将字节[]转换回图像。

public static byte[] ImageToByte(Image img) 
{ 
    ImageConverter converter = new ImageConverter(); 
    return (byte[])converter.ConvertTo(img, typeof(byte[])); 
} 

public static Image ImageFromByte(byte[] image) 
{ 
    ImageConverter ic = new ImageConverter(); 
    Image img = (Image)ic.ConvertFrom(image); 
    return img; 
} 

Answer 2

下面的链接将帮助您：

http://social.msdn.microsoft.com/forums/en-US/winformsdatacontrols/thread/c3fae255-9d2e-45e9-b830-58d544fc43ee/

转换将在上面的链接的下面几行：

using (FileStream fs = fi.OpenRead()) 

        { 

          bData = new byte[fi.Length]; 

          int nReadLength = fs.Read(bData,0, (int)(fi.Length)); 

        } 

希望这有助于...

Answer 3

using (var connection = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\BlankDatabase.mdb")) 
{ 
    connection.Open(); 

    // Create table 
    using (var command = connection.CreateCommand()) 
    { 
     command.CommandText = @" 
      CREATE TABLE FileTable (
       FileName VARCHAR(255), 
       File IMAGE) 
      "; 
     command.ExecuteNonQuery(); 
    } 

    var imageContent = File.ReadAllBytes(@"C:\logo.png"); 

    // upload image to the table 
    using (var command = connection.CreateCommand()) 
    { 
     command.CommandText = @" 
      INSERT INTO FileTable (FileName, File) 
      VALUES (@FileName, @File) 
      "; 
     command.Parameters.AddWithValue("@FileName", "Logo"); 
     command.Parameters.AddWithValue("@File", imageContent); 
     command.ExecuteNonQuery(); 
    } 

    // retreive image from the table 
    using (var command = connection.CreateCommand()) 
    { 
     command.CommandText = @" 
      SELECT File 
      FROM FileTable 
      WHERE FileName = 'Logo' 
      "; 
     var readImageContent = (byte[])command.ExecuteScalar(); 
     File.WriteAllBytes(@"C:\logo1.png", readImageContent); 
    } 

    // alter image from the table 
    using (var command = connection.CreateCommand()) 
    { 
     command.CommandText = @" 
      UPDATE FileTable 
      SET File = @File 
      WHERE FileName = 'Logo' 
      "; 
     command.Parameters.AddWithValue("@File", imageContent); 
     command.ExecuteNonQuery(); 
    } 

    // delete image from the table 
    using (var command = connection.CreateCommand()) 
    { 
     command.CommandText = @" 
      DELETE FROM FileTable 
      WHERE FileName = 'Logo' 
      "; 
     command.ExecuteNonQuery(); 
    } 
} 

在此代码中BlankDatabase.mdb是一个空的MS Access数据库文件。