Determine BLOB SIZE through datareader

Question

I want to execute a datareader with blobs in it. I can do this if I know how big the blobs are and allocate a byte[] that is larger (using .GetBytes()) However I don't always know how big that is. The database type has a limit but for an MSSQL image field it is 2GB (I think). I can't allocate that so I need to know the actual size of the BLOB data. How can I use the SqlDataReader to determine the size of a blob on a particular row so that I can allocate a big enough byte[] for it? I'd post some code but I'm actually doing this in Delphi not C# and I don't want to get caught up in tangential arguments. Thanks!

spgilmore · Answer

It says :  If you pass a buffer that is a null reference (Nothing in Visual Basic) GetBytes returns the length of the field in bytes.  The defined field type size is not what I want but what it actually returns is the blob data size which IS what I want. That's why I didn't try it before. Thanks!

sjones · Answer

Search for Obtaining BLOB Values from a Database in on-line help. When you call GetBytes() passing a null byte array the return value is the size of the array you need rather than the data.