C#怎样读取数据库中Image类型？在线等！！

存进去了就可以用流文件读出来 然后绘制到屏幕上.

class MyBitmap

{

private int width//位图的宽

public int Width

{

get { return width}

set { width = value}

}

private int height//位图的高

public int Height

{

get { return height}

set { height = value}

}

private int postColor//颜色深度

public int PostColor

{

get { return postColor}

set { postColor = value}

}

private Bitmap mBitmap//位图内置对象,引用系统内置Bitmap

public Bitmap MBitmap

{

get { return mBitmap}

set { mBitmap = value}

}

/// <summary>

/// 构造方法,构造一个Bitmap类

/// </summary>

/// <param name="fileurl">文件路径,包含文件名.</param>

public MyBitmap(string fileurl)

{

FileStream fs = new FileStream(fileurl, FileMode.Open)//引用文件 *** 作流

fs.Seek(18, 0)//将流的初始值设为19，即跳过18位.

int wbmp1 = fs.ReadByte()//读取宽的第一位

int wbmp2 = fs.ReadByte()//读取宽的第二位

int wbmp3 = fs.ReadByte()//读取宽的第三位

fs.ReadByte()//第四位在这里用不到.

int hbmp1 = fs.ReadByte()//读取高的第一位

int hbmp2 = fs.ReadByte()//读取高的第二位

int hbmp3 = fs.ReadByte()//读取高的第三位,第四位依然用不到.

Width = wbmp1 | wbmp2 <<8 | wbmp3 <<16//位移运算.得到三个位组成的一个int类型的变量,即位图的宽.

Height = hbmp1 | hbmp2 <<8 | hbmp3 <<16//位移运算.得到三个位组成的一个int类型的变量,即位图的高.

//取得颜色深度,即为多少位的图.在文件头的29位.

fs.Seek(28, 0)//跳过28位.

postColor = fs.ReadByte()//读取第29位,即颜色深度.

MBitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb)//实例化Bitmap类

fs.Seek(54, 0)//跳过文件头,即从第55位开始.

for (int Ycount = 0Ycount <MBitmap.HeightYcount++)//双层循环,遍历bmp数组,分别调用SetPixel方法

{

for (int Xcount = 0Xcount <MBitmap.WidthXcount++)

{

int a = fs.ReadByte()

int b = fs.ReadByte()

int c = fs.ReadByte()

int color = a | b <<8 | c <<16

//因为行序是颠倒的,所以要让它倒回来,需要用行高减去它当前的行数再减一,防止越界.

MBitmap.SetPixel(Xcount, MBitmap.Height - Ycount - 1, Color.FromArgb(color))

}

}

fs.Close()//关闭文件流

}

/// <summary>

/// 绘制位图

/// </summary>

/// <param name="g">Graphics对象g</param>

public void Draw(Graphics g,Bitmap bmp)

{

g.DrawImage(bmp, 0, 0)//绘制bmp图

}

public Bitmap SmallBitmap(Bitmap b)

{

int w = b.Width / 2

int h = b.Height / 2

Bitmap bmp = new Bitmap(b, w, h)

for (int Ycount = 0Ycount <hYcount++)

{

for (int Xcount = 0Xcount <wXcount++)

{

Color c1 = b.GetPixel(Xcount * 2, Ycount * 2)

Color c2 = b.GetPixel(Xcount * 2, Ycount * 2 + 1)

Color c3 = b.GetPixel(Xcount * 2 + 1, Ycount * 2)

Color c4 = b.GetPixel(Xcount * 2 + 1, Ycount * 2 + 1)

int c1r = (16711680 &c1.ToArgb()) >>16

int c1g = (65280 &c1.ToArgb()) >>8

int c1b = (255 &c1.ToArgb())

int c2r = (16711680 &c2.ToArgb()) >>16

int c2g = (65280 &c2.ToArgb()) >>8

int c2b = (255 &c2.ToArgb())

int c3r = (16711680 &c3.ToArgb()) >>16

int c3g = (65280 &c3.ToArgb()) >>8

int c3b = (255 &c3.ToArgb())

int c4r = (16711680 &c4.ToArgb()) >>16

int c4g = (65280 &c4.ToArgb()) >>8

int c4b = (255 &c4.ToArgb())

int cr = (c1r + c2r + c3r + c4r) / 4

int cg = (c1g + c2g + c3g + c4g) / 4

int cb = (c1b + c2b + c3b + c4b) / 4

bmp.SetPixel(Xcount, Ycount, Color.FromArgb((cr == 255 &&cg == 0 &&cb == 255) ? 0 : 255, cr, cg, cb))

}

}

return bmp

}

}

这里有一段我写的对bmp类型图片的绘制，你可以看下

如果是用sql

语句插入数据的话如下：

insert

into

table(a,b,c)

value(1,2,3)

--若b需要使用默认值,如下即可:

insert

into

table(a,c)

value(1,3)

insert

into

table

value(1,2,3)

insert

into

table

select

a,b,c

from

table1

insert

into

a

select

*

from

b

从根本的上说，都是insert用法。没有利避，只看需要。

你仔细分析一下，就会发现，还是标准的insert

insert

into

表名

[表列]value[对应值]

要是变化就在前面的表列和对应值上，怎么用表列，可省略，可以动态的取得。

对应值的获取方法就更多了，可以动态的输入，比如一些存储过程。还可以从别的表中取得，也可以固定时，还可以用一些函数，等等

读取... 读取长二进制为图片..

string sql = "select photo from studentinfo where studentid = " + this.Tag.ToString()

OleDbCommand cmd = new OleDbCommand(sql, connection1)

if (Convert.DBNull != cmd.ExecuteScalar())

pictureBox1.Image = Image.FromStream(new MemoryStream((Byte[])cmd.ExecuteScalar()))

放大就不知道了

保存:

string filename= textBox1.Text//"c:\\IMG_0117.jpg"

BinaryReader reader=null

FileStream myfilestream = new FileStream(filename,FileMode.Open)

try

{

reader=new BinaryReader(myfilestream)

byte[] image = reader.ReadBytes((int)myfilestream.Length)

using (SqlConnection conn = new SqlConnection("server=test05database=esdb2uid=datatranpwd=qyrl"))

{

using (SqlCommand command = conn.CreateCommand())

{

command.CommandText =@"INSERT INTO photo(photo) VALUES (@photo)"

command.Parameters.Add("@photo", image)

conn.Open()

command.ExecuteNonQuery()

conn.Close()

MessageBox.Show("文件保存成功！","提示",MessageBoxButtons.OK,MessageBoxIcon.Information)

}

}

}

catch(IOException ee)

{

MessageBox.Show(ee.Message.ToString())

}

finally

{

if(reader!=null)

reader.Close()

}

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