c#关于图片在sql server的操作

读一个图片

MemoryStream stream = new MemoryStream ();

SqlConnection conn = new SqlConnection

("server=localhost;database=pubs;uid=sa;pwd=");

try {

conn.Open ();

SqlCommand cmd = new SqlCommand

("select logo from pub_info where pub_id='0736'", conn);

byte[] blob = (byte[]) cmd.ExecuteScalar ();

stream.Write (blob, 0, blob.Length);

Bitmap bitmap = new Bitmap (stream);

// TODO: Use the bitmap

bitmap.Dispose ();

}

catch (SqlException ex) {

// TODO: Handle the exception

}

finally {

stream.Close ();

conn.Close ();

}

写入

FileStream stream = new FileStream ("Logo.jpg", FileMode.Open, FileAccess.Read);

byte[] blob = new byte[stream.Length];

stream.Read (blob, 0, (int) stream.Length);

stream.Close ();

SqlConnection conn = new SqlConnection

("server=localhost;database=pubs;uid=sa;pwd=");

try {

conn.Open ();

SqlCommand cmd = new SqlCommand

("insert into pub_info (pub_id, logo) values ('9937', @logo)",

conn);

cmd.Parameters.Add ("@logo", blob);

cmd.ExecuteNonQuery ();

}

catch (SqlException ex) {

// TODO: Handle the exception

}

finally {

conn.Close ();

}

我们可以把任意类型的文件保存到SQL Server中，在进行例子之前，先建立测试用表格，TestFile.sql：

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[TestFiles]')

and OBJECTPROPERTY(id, N'IsUserTable') = 1)

drop table [dbo].[TestFiles]

GO

CREATE TABLE [dbo].[TestFiles] (

[id] [int] IDENTITY (1, 1) NOT NULL ,

[MyFileName] [varchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL ,

[FileType] [varchar] (50) COLLATE Chinese_PRC_CI_AS NOT NULL ,

[MyFile] [image] NOT NULL

) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO

下面创建上传表单：

一旦提交了表单，我们使用HtmlInputFile类的PostedFile属性来访问我们上载的文件，用HttpPostedFile类的属性和方法来进行读取、保存上载文件和得到上载文件的其它信息。这里我们不使用SaveAs方法，因为它是用来保存文件的。我们要把数据保存到数据库中，我们使用InputStream属性，它用来初始化流来读取我们的数据。同时，我们使用ContentLength来读取文件大小，ContentType读取文件类型。然后创建byte数组，把文件流保存进该数组，然后保存到数据库即可。

下面就是完整的代码【CS版本】UploadFile.aspx：

<% @Page Language=""C#"" %>

<% @Import Namespace=""System.IO"" %>

<% @ Import Namespace=""System.Data"" %>

<% @ Import Namespace=""System.Data.SqlClient"" %>

<script runat=""server"">

public void UploadBtn_Click (Object sender, EventArgs e){

//得到提交的文件

Stream fileDataStream = MyFile.PostedFile.InputStream;

//得到文件大小

int fileLength = MyFile.PostedFile.ContentLength;

//创建数组

byte[] fileData = new byte[fileLength];

//把文件流填充到数组

fileDataStream.Read(fileData,0,fileLength);

//得到文件名字

string fileTitle = MyFileName.Value;

//得到文件类型

string fileType = MyFile.PostedFile.ContentType;

//构建数据库连接，SQL语句，创建参数

SqlConnection connection = new SqlConnection(""Server=.;uid=sa;pwd=;Database=TestUploadFile"");

SqlCommand command = new SqlCommand (""INSERT INTO TestFiles (MyFileName,MyFile,FileType)"" +

""VALUES (@MyFileName,@MyFile,@FileType)"", connection);

SqlParameter paramTitle = new SqlParameter (""@MyFileName"", SqlDbType.VarChar,35);

paramTitle.Value = fileTitle;

command.Parameters.Add(paramTitle);

SqlParameter paramData = new SqlParameter (""@MyFile"", SqlDbType.Image);

paramData.Value = fileData;

command.Parameters.Add(paramData);

SqlParameter paramType = new SqlParameter (""@FileType"", SqlDbType.VarChar,25);

paramType.Value = fileType;

command.Parameters.Add(paramType);

//打开连接，执行查询

connection.Open();

command.ExecuteNonQuery();

connection.Close();

Message.Text=""你的文件已经成功上载"";

MyFileName.Value = """";

}

</script>

<hr>

<asp:label id=""Message"" Text=""选择文件和文件名字："" runat=""server""/>

<hr>

<form method=""post"" enctype=""multipart/form-data"" runat=""server"">

<b>文件名字：</b><input id=""MyFileName"" type=""text"" runat=""server"">

<P>

<b>文件：</b><input id=""MyFile"" type=""file"" runat=""server"">

<br/><br/>

<input type=submit value=""开始上传"" OnServerclick=""UploadBtn_Click"" runat=""server"">

</form>

一旦我们上载成功，我们可以对文件进行浏览：只需要设置页面的MIME类型，然后用Response对象的BinaryWrite()进行输出。

ShowUploadFile.aspx

<% @Page Language=""C#"" %>

<% @Import Namespace=""System.IO"" %>

<% @ Import Namespace=""System.Data"" %>

<% @ Import Namespace=""System.Data.SqlClient"" %>

<script runat=""server"">

private void Page_Load(Object sender, EventArgs e) {

string sql=""SELECT * FROM TestFiles"";

SqlConnection connection = new SqlConnection(""Server=.;uid=sa;pwd=;Database=TestUploadFile"");

SqlCommand command = new SqlCommand(sql, connection);

connection.Open();

FileList.DataSource = command.ExecuteReader();

FileList.DataBind();

connection.Close();

}

</script>

<form runat=""server"">

<asp:DataGrid id=""FileList"" runat=""server""

BorderColor=""orange"" BorderWidth=""2"" CellPadding=""4""

AutoGenerateColumns=""false"" ShowHeader=""true"" Align=""center"">

<HeaderStyle BorderColor=""White"" BackColor=""black"" ForeColor=""White""

Font-Bold=""True"" Font-Size=""9"" HorizontalAlign=""Center""/>

<Columns>

<asp:TemplateColumn HeaderText=""文件名字"">

<ItemTemplate>

<b>

<%# DataBinder.Eval(Container.DataItem, ""MyFileName"") %>

</b>

</ItemTemplate>

</asp:TemplateColumn>

<asp:TemplateColumn HeaderText=""类型"">

<ItemTemplate>

<b>

<%# DataBinder.Eval(Container.DataItem, ""FileType"") %>

</b>

</ItemTemplate>

</asp:TemplateColumn>

<asp:TemplateColumn HeaderText=""查看"">

<ItemTemplate>

<b>

<a href='ShowFile.aspx?ID=<%# DataBinder.Eval(Container.DataItem, ""ID"") %>'>查看文件</a>

</b>

</ItemTemplate>

</asp:TemplateColumn>

</Columns>

</asp:DataGrid>

</form>

ShowFile.aspx

<% @Page Language=""C#"" %>

<% @Import Namespace=""System.IO"" %>

<% @ Import Namespace=""System.Data"" %>

<% @ Import Namespace=""System.Data.SqlClient"" %>

<script runat=""server"">

private void Page_Load(Object sender, EventArgs e) {

string sql=""SELECT * FROM TestFiles WHERE ID = '"" + Request.QueryString[""ID""] + ""'"";

SqlConnection connection = new SqlConnection(""Server=.;uid=sa;pwd=;Database=TestUploadFile"");

SqlCommand command = new SqlCommand(sql, connection);

connection.Open();

SqlDataReader dr = command.ExecuteReader();

if(dr.Read()){

Response.Clear();

Response.AddHeader(""Content-Type"",dr[""FileType""].ToString());

Response.BinaryWrite((byte[])dr[""MyFile""]);

}

dr.Close();

connection.Close();

}

</script>

另外需要注意的是：对exe，zip文件等还要进一步进行处理，以直接进行下载。