Retrieve the uniqueidentifier key value for a record

Question

i have DB field Picture datatype = uniqueidentifier , i want to get picture show on web page asp.net C#

Answer 1

Hello @natsit kaewsungharn

Not knowing how you interact with data let' say it's via a SqlClient connection and command using a where condition uniqueidentifier maps to a string so you can pass a string to represent a uniqueidentifier. Then in your SELECT place the column name for the picture in. Or via Entity Framework similarly use a .Where and .Select.

In either case the picture is a byte array, depending on the column type, image or varbinary(max) you can return a image using the following code by passing in the byte array. If using .NET Core then you need the NuGet package System.Drawing.Common.

public class ImageHelpers  
{  
    // for image column  
    public static Image ByteArrayToImage1(byte[] contents)  
    {  
        using (var ms = new MemoryStream(contents))  
        {  
            return Image.FromStream(ms);  
        }  
    }  
    // for varbinary(max)  
    public static Image ByteArrayToImage(byte[] contents)  
    {  
        var converter = new ImageConverter();  
        var image = (Image)converter.ConvertFrom(contents);  
  
        return image;  
    }  
}