Determine BLOB SIZE through datareader

spgilmore

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!

2 Replies

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spgilmore22y ago
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!
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sjones22y ago
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.
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