having problem with inserting an image into a database

    if (uploadimg.PostedFile != null && uploadimg.PostedFile.FileName != "")
    {

        string img_id = "1";
        byte[] myimage = new byte[uploadimg.PostedFile.ContentLength];
        HttpPostedFile Image = 开发者_C百科uploadimg.PostedFile;
        Image.InputStream.Read(myimage, 0, (int)uploadimg.PostedFile.ContentLength);

        SqlConnection myConnection = new SqlConnection("Data Source=DELL-PC\\SQLEXPRESS;Initial Catalog=eclass;Persist Security Info=True;integrated security = true");
        SqlCommand storeimage = new SqlCommand("INSERT INTO ImageGallery " + "(img_id,image_Size,image_Content) " + " values (@img_id,@imagesize,@image)", myConnection);
        storeimage.Parameters.AddWithValue("@img_id",img_id);
       // storeimage.Parameters.Add("@id",SqlDbType.VarChar,100) = uploadimg.PostedFile.ContentType;
        //storeimage.Parameters.Add('@id',id);
        storeimage.Parameters.Add("@imagesize", SqlDbType.BigInt, 99999).Value = uploadimg.PostedFile.ContentLength;
        storeimage.Parameters.Add("@image", SqlDbType.Image, myimage.Length).Value = myimage;



        try
        {
            myConnection.Open();
            storeimage.ExecuteNonQuery();
            myConnection.Close();

        }
        catch (Exception e)
        {
            Response.Write(e.ToString());
        }
    }

what changes should i make in my c# code so that i can avoid my sql exception of primary key constrain as i hav used my trigger

create trigger trig_image on ImageGallery After insert as begin declare @id int; set @id=1; update ImageGallery set img_id='img'+cast(@id as varchar(10)) set @id=@id+1; end go

and columns are img_id varchar(50),image_size bigint,image_content image

By default, SQL Server will try to convert 'img' to an integer to add @id to it. Change:

set img_id = 'img' + @id

to

set img_id = 'img' + cast(@id as varchar(12))

Your trigger is very dangerous..... the code as you have it will update all rows in your table ImageGallery everytime an insert happens - is that really what you want??

Also - to have a separate column with img001, img002 etc., I would use a computed column:

ALTER TABLE dbo.ImageGallery
  ADD ImageText AS 'img' + CAST(img_id AS VARCHAR(5)) PERSISTED

With this, you get a new column called ImageText which will hold values img1, img2 and so forth - automatically, without any need for a messy trigger or anything - it just works!

The problem is in your Trigger statement.

You have to explicitly convert the @id variable to a varchar.

declare @id int; 
set @id=1; 

update ImageGallery 
set img_id='img'+ convert(varchar(10), @id)

set @id=@id+1

EDIT:

You are probably getting a PK constraint violation because:

• You are trying to update all img_id's rather than the one you have just inserted
• You are always setting the @id variable to 1 so each time the trigger runs the @Id value will always be 1

Another option would be to change your table structure and have img_id as an integer identity column. This will save you from having to manually calculate the ID as SQL Server will automatically increment the value on each insert.

You can easily add the 'img' prefix before displaying to the client.

e.g

example select

Select 'img' + convert(varchar(10), img_id) as 'Formatted_Img_id'
from ImageGallery

example update

Update ImageGallery
Set Description = 'blah blah test'
Where img_id = Replace(img_id, 'img','')

What is the date type of the field image_id?

I assume it's of type INT. I recommend using date type varchar.