c#在sql中存取图片image示例_C#教程

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(1)控制台应用程序下演示插入图片

public void InsertIMG()
{
//将需要存储的图片读取为数据流
FileStream fs = new FileStream(@"E:\c.jpg", FileMode.Open,FileAccess.Read);
Byte[] btye2 = new byte[fs.Length];
fs.Read(btye2 , 0, Convert.ToInt32(fs.Length));
fs.Close();

using (SqlConnection conn = new SqlConnection(sqlconnstr))
{
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = "insert into T_Img(imgfile) values(@imgfile)";
SqlParameter par = new SqlParameter("@imgfile", SqlDbType.Image);
par.Value = bt;
cmd.Parameters.Add(par);

int t=(int)(cmd.ExecuteNonQuery());
if (t > 0)
{
Console.WriteLine("插入成功");
}
conn.Close();
}
}

(2)控制台应用程序下读出并生成图片到物理位置

public void Read()
{
byte[] MyData = new byte[0];
using (SqlConnection conn = new SqlConnection(sqlconnstr))
{
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = "select * from T_img";
SqlDataReader sdr = cmd.ExecuteReader();
sdr.Read();
MyData = (byte[])sdr["ImgFile"];//读取第一个图片的位流
int ArraySize= MyData.GetUpperBound(0);//获得数据库中存储的位流数组的维度上限,用作读取流的上限

FileStream fs = new FileStream(@"c:\00.jpg", FileMode.OpenOrCreate, FileAccess.Write);
fs.Write(MyData, 0, ArraySize);
fs.Close();   //-- 写入到c:\00.jpg。
conn.Close();
Console.WriteLine("读取成功");//查看硬盘上的文件
}
}

(3)Web下picshow.aspx页将图片读取出来并写入到浏览器上呈现

public void Read()
{
byte[] MyData = new byte[0];
using (SqlConnection conn = new SqlConnection(sqlconnstr))
{
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = "select * from T_img";
SqlDataReader sdr = cmd.ExecuteReader();
sdr.Read();
MyData = (byte[])sdr["ImgFile"];
Response.ContentType = "image/gif";
Response.BinaryWrite(MyData);
conn.Close();
Response.Write("读取成功");
}

(4)在web中可以如上picshow.aspx页面读取并显示图片,而真正引用该图片时如下示例

<img src="picshow.aspx" width="500" height="300" />

 (5)Winform下将图片写入到sql数据库image类型字段中的方法和以上方法基本一致,仅区别于可以利用多个对话框来帮助选取存储图片等,各个属性可以方便的利用上

(6)Winform下读取图片在picturebox控件中显示出来

方法一:利用MemoryStream 和System.Drawing.Image

public void Read()
{
byte[] MyData = new byte[0];
using (SqlConnection conn = new SqlConnection(sqlconnstr))
{
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = "select * from T_img";
SqlDataReader sdr = cmd.ExecuteReader();
sdr.Read();
MyData = (byte[])sdr["ImgFile"];

MemoryStream mystream = new MemoryStream(MyData);
//用指定的数据流来创建一个image图片
System.Drawing.Image img = System.Drawing.Image.FromStream(mystream, true);

System.Windows.Forms.PictureBox picbox = new PictureBox();
picbox.Image = img;
picbox.Left = 30;
picbox.Top = 80;
picbox.Width = 800;
picbox.Height = 500;
this.Controls.Add(picbox);

mystream.Close();
conn.Close();
}
}

方法二:将流直接读取成图片并写入到物理位置,然后再行利用该图片呈现

void Read()
{
using (SqlConnection conn = new SqlConnection(sqlconnstr))
{
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = "select * from T_img";
SqlDataReader sdr = cmd.ExecuteReader();
sdr.Read();

byte[] Image_img = (byte[])sdr["ImgFile"];
if (Image_img.Length == 0)
{
return;
}
int filelength = Image_img.Length;
string imageName = "1.jpg";
string myUrl = Environment.CurrentDirectory + "\\" + imageName;
FileStream fs = new FileStream(myUrl, FileMode.OpenOrCreate,FileAccess.Write);
BinaryWriter BW = new BinaryWriter(fs);
BW.BaseStream.Write(Image_img, 0, filelength);
BW.Flush();
BW.Close();
System.Windows.Forms.PictureBox picbox = new PictureBox();

//为picbox添加图片方法一
//picbox.ImageLocation = myUrl;
//picbox.Width = 800;
//picbox.Height = 300;

 

//为picbox添加图片方法二
Bitmap bitmap = new Bitmap(myUrl);
picbox.Width = 100;//bitmap.Width;
picbox.Height = 80;//bitmap.Height;
picbox.Image = (Image)bitmap;
picbox.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
picbox.Left = 20;
picbox.Top = 30;

this.Controls.Add(picbox);
conn.Close();

}
}

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