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Storing and Retrieving Images from SQL Serve

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原文? Storing and Retrieving Images from SQL Server using Microsoft .NET

Introduction

This article is about storing and retrieving images from database in Microsoft .NET using C#.

Tools Used

  • SQL Server 2000
  • Microsoft .NET Version 1.1
  • C# (Windows Forms based application)

Storing Images

  1. Create a table in a SQL Server 2000 database which has at least one field of type? IMAGE .

    Here is the script I used:

    ?Collapse ?|? Copy Code
              
                CREATE
              
              
                TABLE
              
               [dbo].[tblImgData] (
    
    
    
            [ID] [
              
                int
              
              ] 
              
                NOT
              
              
                NULL
              
               ,
    
    
    
            [Name] [
              
                varchar
              
              ] (
              
                50
              
              ) 
              
                COLLATE
              
               SQL_Latin1_General_CP1_CI_AS 
              
                NULL
              
               ,
    
    
    
            [Picture] [
              
                image
              
              ] 
              
                NULL
              
               
    
    
    
    ) 
              
                ON
              
               [
              
                PRIMARY
              
              ] TEXTIMAGE_ON [
              
                PRIMARY
              
              ]
            
  2. Actually? IMAGE ?field is just holding the reference to the page containing the binary data so we have to convert our image into bytes.
    1. I used a file open dialog box to locate the file.
      ?Collapse ?|? Copy Code
                    
                      this
                    
                    .openFileDialog1.ShowDialog(
                    
                      this
                    
                    );
      
      
                    
                      string
                    
                     strFn=this.openFileDialog1.FileName;
                  
    2. By using? FileInfo ?class, I retrieved the file size:
      ?Collapse ?|? Copy Code
                    FileInfo fiImage=new FileInfo(strFn);
                  
    3. Declare an array of that size.
      ?Collapse ?|? Copy Code
                    
                      this
                    
                    .m_lImageFileLength=fiImage.Length;
      
      m_barrImg=new 
                    
                      byte
                    
                    [Convert.ToInt32(
                    
                      this
                    
                    .m_lImageFileLength)];
                  
    4. By using? FileStream ?object, I filled the byte array.
      ?Collapse ?|? Copy Code
                    FileStream fs=new FileStream(strFn,FileMode.Open, 
      
                        FileAccess.Read,FileShare.Read);
      
      
                    
                      int
                    
                     iBytesRead=fs.Read(m_barrImg,
                    
                      0
                    
                    ,
      
                     Convert.ToInt32(
                    
                      this
                    
                    .m_lImageFileLength));
      
      fs.Close();
                  

    Complete Load Image Code

    ?Collapse ?|? Copy Code
              
                protected
              
              
                void
              
               LoadImage()
    
    {
    
        
              
                try
              
              
    
        {
    
            
              
                this
              
              .openFileDialog1.ShowDialog(
              
                this
              
              );
    
            
              
                string
              
               strFn=this.openFileDialog1.FileName;
    
            
              
                this
              
              .pictureBox1.Image=Image.FromFile(strFn);
    
            FileInfo fiImage=new FileInfo(strFn);
    
            
              
                this
              
              .m_lImageFileLength=fiImage.Length;
    
            FileStream fs=new FileStream(strFn,FileMode.Open, 
    
                              FileAccess.Read,FileShare.Read);
    
            m_barrImg=new 
              
                byte
              
              [Convert.ToInt32(
              
                this
              
              .m_lImageFileLength)];
    
            
              
                int
              
               iBytesRead = fs.Read(m_barrImg,
              
                0
              
              , 
    
                             Convert.ToInt32(
              
                this
              
              .m_lImageFileLength));
    
            fs.Close();
    
        }
    
        
              
                catch
              
              (Exception ex)
    
        {
    
            MessageBox.Show(ex.Message);
    
        }
    
    }
            
  3. Saving byte array data to database.
    1. Create command text to insert record.
      ?Collapse ?|? Copy Code
                    
                      this
                    
                    .sqlCommand1.CommandText= 
      
        
                    
                      "
                    
                    
                      INSERT INTO tblImgData(ID,Name,Picture)"
                    
                     + 
      
        
                    
                      "
                    
                    
                       values(@ID,@Name,@Picture)"
                    
                    ;
                  
    2. Create parameters.
      ?Collapse ?|? Copy Code
                    
                      this
                    
                    .sqlCommand1.Parameters.Add(
                    
                      "
                    
                    
                      @ID"
                    
                    ,
      
                 System.Data.SqlDbType.Int, 
                    
                      4
                    
                    );
      
      
                    
                      this
                    
                    .sqlCommand1.Parameters.Add(
                    
                      "
                    
                    
                      @Name"
                    
                    , 
      
                 System.Data.SqlDbType.VarChar, 
                    
                      50
                    
                    );
      
      
      
      
                    
                      this
                    
                    .sqlCommand1.Parameters.Add(
                    
                      "
                    
                    
                      @Picture"
                    
                    , 
      
                 System.Data.SqlDbType.Image);
                  

      Notice “ @Picture ” has “ SqlDbType.Image ” because it is of? IMAGE ?type Field.

    3. Provide the value to the parameters.
      ?Collapse ?|? Copy Code
                    
                      this
                    
                    .sqlCommand1.Parameters[
                    
                      "
                    
                    
                      @ID"
                    
                    ].Value=this.editID.Text;
      
      
                    
                      this
                    
                    .sqlCommand1.Parameters[
                    
                      "
                    
                    
                      @Name"
                    
                    ].Value=this.editName.Text;
      
      
      
      
                    
                      this
                    
                    .sqlCommand1.Parameters[
                    
                      "
                    
                    
                      @Picture"
                    
                    ].Value=this.m_barrImg;
                  

      this .m_barrImg ” is a byte array which we filled in the previous step.

    4. Now execute non-query for saving the record to the database.
      ?Collapse ?|? Copy Code
                    
                      int
                    
                     iresult=this.sqlCommand1.ExecuteNonQuery();
                  

    Complete Save Image Code

    ?Collapse ?|? Copy Code
              
                private
              
              
                void
              
               btnSave_Click(
              
                object
              
               sender, System.EventArgs e)
    
    {
    
        
              
                try
              
              
    
        {
    
            
              
                this
              
              .sqlConnection1.Open();
    
            
              
                if
              
               (sqlCommand1.Parameters.Count ==0 )
    
            {
    
                
              
                this
              
              .sqlCommand1.CommandText=
              
                "
              
              
                INSERT INTO tblImgData(ID,"
              
               + 
    
                               
              
                "
              
              
                 Name,Picture) values(@ID,@Name,@Picture)"
              
              ;
    
                
              
                this
              
              .sqlCommand1.Parameters.Add(
              
                "
              
              
                @ID"
              
              , 
    
                                 System.Data.SqlDbType.Int,
              
                4
              
              );
    
                
              
                this
              
              .sqlCommand1.Parameters.Add(
              
                "
              
              
                @Name"
              
              , 
    
                                 System.Data.SqlDbType.VarChar,
              
                50
              
              );
    
                
              
                this
              
              .sqlCommand1.Parameters.Add(
              
                "
              
              
                @Picture"
              
              , 
    
                                 System.Data.SqlDbType.Image);
    
            }
    
    
    
            
              
                this
              
              .sqlCommand1.Parameters[
              
                "
              
              
                @ID"
              
              ].Value=this.editID.Text;
    
            
              
                this
              
              .sqlCommand1.Parameters[
              
                "
              
              
                @Name"
              
              ].Value=this.editName.Text;
    
            
              
                this
              
              .sqlCommand1.Parameters[
              
                "
              
              
                @Picture"
              
              ].Value=this.m_barrImg;
    
    
    
            
              
                int
              
               iresult=this.sqlCommand1.ExecuteNonQuery();
    
            MessageBox.Show(Convert.ToString(iresult));
    
        }
    
        
              
                catch
              
              (Exception ex)
    
        {
    
            MessageBox.Show(ex.Message);
    
        }
    
        
              
                finally
              
              
    
        {
    
            
              
                this
              
              .sqlConnection1.Close();
    
        }
    
    }
            

Retrieving Image

Retrieving images from the database is the exact reverse process of saving images to the database.

  1. First create command text to retrieve record.
    ?Collapse ?|? Copy Code
              SqlCommand cmdSelect = 
              
                new
              
               SqlCommand(
              
                "
              
              
                select Picture"
              
               + 
    
                           
              
                "
              
              
                 from tblImgData where ID=@ID"
              
              , 
    
                           
              
                this
              
              .sqlConnection1);
            
  2. Create parameter for the query.
    ?Collapse ?|? Copy Code
              cmdSelect.Parameters.Add(
              
                "
              
              
                @ID"
              
              ,SqlDbType.Int,
              
                4
              
              );
            
  3. Provide value to the parameter.
    ?Collapse ?|? Copy Code
              cmdSelect.Parameters[
              
                "
              
              
                @ID"
              
              ].Value=this.editID.Text;
            
  4. Open database connection and execute “ ExecuteScalar ” because we want only “ IMAGE ” column data back.
    ?Collapse ?|? Copy Code
              
                byte
              
              [] barrImg=(
              
                byte
              
              [])cmdSelect.ExecuteScalar();
            

    As the execute scalar returns data of “ Object ” data type, we cast it to? byte ?array.

  5. Save this data to a temporary file.
    ?Collapse ?|? Copy Code
              
                string
              
               strfn=Convert.ToString(DateTime.Now.ToFileTime());
    
    FileStream fs=new FileStream(strfn,FileMode.CreateNew,FileAccess.Write);
    
    fs.Write(barrImg,
              
                0
              
              ,barrImg.Length);
    
    fs.Flush();
    
    fs.Close();
            
  6. And display the image anywhere you want to display.
    ?Collapse ?|? Copy Code
              pictureBox1.Image=Image.FromFile(strfn);
            

Complete Image Retrieving Code

?Collapse ?|? Copy Code
      
        private
      
      
        void
      
       btnLoad_Click(
      
        object
      
       sender, System.EventArgs e)

{

    
      
        try
      
      

    {

        SqlCommand cmdSelect=new SqlCommand(
      
        "
      
      
        select Picture"
      
       + 

              
      
        "
      
      
         from tblImgData where ID=@ID"
      
      ,
      
        this
      
      .sqlConnection1);

        cmdSelect.Parameters.Add(
      
        "
      
      
        @ID"
      
      ,SqlDbType.Int,
      
        4
      
      );

        cmdSelect.Parameters[
      
        "
      
      
        @ID"
      
      ].Value=this.editID.Text;



        
      
        this
      
      .sqlConnection1.Open();

        
      
        byte
      
      [] barrImg=(
      
        byte
      
      [])cmdSelect.ExecuteScalar();

        
      
        string
      
       strfn=Convert.ToString(DateTime.Now.ToFileTime());

        FileStream fs=new FileStream(strfn, 

                          FileMode.CreateNew, FileAccess.Write);

        fs.Write(barrImg,
      
        0
      
      ,barrImg.Length);

        fs.Flush();

        fs.Close();

        pictureBox1.Image=Image.FromFile(strfn);

    }

    
      
        catch
      
      (Exception ex)

    {

        MessageBox.Show(ex.Message);

    }

    
      
        finally
      
      

    {

        
      
        this
      
      .sqlConnection1.Close();

    }

}
    

Bibliography

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found? here

Storing and Retrieving Images from SQL Server using Microsoft .NET


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