在 Visual C# 中直接将一个图片从数据库复制到 PictureBox 控件

[code]CREATE TABLE BLOBTest
(
BLOBID INT IDENTITY NOT NULL,
BLOBData IMAGE NOT NULL
)

[code]using System.Data.SqlClient;
using System.IO;
using System.Drawing.Imaging;

[code]    String strCn = "Data Source=localhost;integrated security=sspi;initial catalog=mydata";

[code]try
{
SqlConnection cn = new SqlConnection(strCn);
SqlCommand cmd =  new SqlCommand("INSERT INTO BLOBTest (BLOBData) VALUES (@BLOBData)", cn);
String strBLOBFilePath = @"C:/blue hills.jpg";//Modify this path as needed.

//Read jpg into file stream, and from there into Byte array.
FileStream fsBLOBFile =  new FileStream(strBLOBFilePath,FileMode.Open, FileAccess.Read);
Byte[] bytBLOBData = new Byte[fsBLOBFile.Length];
fsBLOBFile.Read(bytBLOBData, 0, bytBLOBData.Length);
fsBLOBFile.Close();

//Create parameter for insert command and add to SqlCommand object.
SqlParameter prm = new  SqlParameter("@BLOBData", SqlDbType.VarBinary, bytBLOBData.Length, ParameterDirection.Input, false,
0, 0, null, DataRowVersion.Current, bytBLOBData);
cmd.Parameters.Add(prm);

//Open connection, execute query, and close connection.
cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
}catch(Exception ex)
{MessageBox.Show(ex.Message);}

[code]try
{
SqlConnection cn = new SqlConnection(strCn);
cn.Open();

//Retrieve BLOB from database into DataSet.
SqlCommand cmd = new SqlCommand("SELECT BLOBID, BLOBData FROM BLOBTest ORDER BY BLOBID", cn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds, "BLOBTest");
int c = ds.Tables["BLOBTest"].Rows.Count;

if(c>0)
{   //BLOB is read into Byte array, then used to construct MemoryStream,
//then passed to PictureBox.
Byte[] byteBLOBData =  new Byte[0];
byteBLOBData = (Byte[])(ds.Tables["BLOBTest"].Rows[c - 1]["BLOBData"]);
MemoryStream stmBLOBData = new MemoryStream(byteBLOBData);
pictureBox1.Image= Image.FromStream(stmBLOBData);
}
cn.Close();
}
catch(Exception ex)
{MessageBox.Show(ex.Message);}

[code]try
{
SqlConnection cn = new SqlConnection(strCn);
SqlCommand cmd = new SqlCommand("INSERT INTO BLOBTest (BLOBData) VALUES (@BLOBData)", cn);

//Save image from PictureBox into MemoryStream object.
MemoryStream ms  = new MemoryStream();
pictureBox1.Image.Save(ms, ImageFormat.Jpeg);

//Read from MemoryStream into Byte array.
Byte[] bytBLOBData = new Byte[ms.Length];
ms.Position = 0;
ms.Read(bytBLOBData, 0, Convert.ToInt32(ms.Length));

//Create parameter for insert statement that contains image.
SqlParameter prm = new SqlParameter("@BLOBData", SqlDbType.VarBinary, bytBLOBData.Length, ParameterDirection.Input, false,
0, 0,null, DataRowVersion.Current, bytBLOBData);
cmd.Parameters.Add(prm);
cn.Open();
cmd.ExecuteNonQuery();
cn.Close();
}catch(Exception  ex)
{MessageBox.Show(ex.Message);}