how can i insert binary data into a collection using c#.

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More Information on installing the. Net Framework click here. Download full Visual Studio C. NET Examples from this Article. The default behavior of the DataReader is to load incoming data as a row as soon as an entire row of data is available. Binary large objects BLOBs need to be treated differently, however, because they can contain gigabytes of data that cannot be contained in a single use binary data in c#. ExecuteReader method has an overload which will take a CommandBehavior argument to modify the default behavior of the DataReader.

You can pass CommandBehavior. SequentialAccess to the ExecuteReader method to modify the default behavior of the DataReader so that instead of loading rows of data, it will load data sequentially as it is received. This is ideal for use binary data in c# BLOBs or other large data structures. Note that this behavior may differ depending on your data source.

Rather than loading the entire row, SequentialAccess enables the DataReader to load data as a stream. When setting the DataReader to use SequentialAccess, it is i mportant to note the sequence in which you access the fields returned.

The default behavior of the DataReader, which loads an entire row as soon as it is available, allows you to access the fields returned in any order until the next row is read. When using SequentialAccess however, you must access the different fields returned by the DataReader in order.

For example, if your query returns three columns, the third of use binary data in c# is a BLOB, you must return the values of the first and second fields before accessing the BLOB data in the third field. If you access the third field before the first or second fields, the first and second field values will no longer be available.

This is because SequentialAccess has modified the DataReader to return data in sequence and the data will not be available after the DataReader has read past it. You can also use GetString for character data, however to conserve system resources you may not want to load an entire BLOB value into a single string variable.

You can specify a specific buffer size of data to be returned, and a starting location for the first byte or character to be read from the returned data. GetBytes and GetChars will return a long value, which represents the number of bytes or use binary data in c# returned. You can optionally specify an index in the array as a starting position for the data being read. You can write a binary large object BLOB to a database as either binary or character data, use binary data in c# on the type of field at your data source.

The following code example adds employee information to the Employees table in the Northwind database. A photo of the employee is read from a file and added to the Photo field in the table, which is an image field. The Photo field is then read using GetBytes. Notice that the employee id is accessed for the current row of data before the Photo, because the fields must be accessed sequentially. Show "Unable to load file: Example The following code example adds employee information to the Employees table in the Northwind database.

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In the C newsgroup, I've seen quite a lot of code for reading in data from a file like this:. This code is far from guaranteed to work. In particular, the FileStream could be reading just the first 10 bytes of the file into the buffer. The Read method is only guaranteed to block until some data is available or the end of the stream is reached , not until all of the data is available. That's where the return value which is ignored in the above code is vital.

You need to cope with the case where you can't read all of the data in one go, and loop round until you've read what you want. Here's a method which you can use if you want to read from a stream into the whole of an array, not stopping until it's finished:. Sometimes, you don't know the length of the stream in advance for instance a network stream and just want to read the whole lot into a buffer.

Here's a method to do just that:. While the above is simple, it's not terribly efficient, as it ends up copying the data at the very end, and probably several times between. Here's some code which works well if you know the expected length of data to start with.

While you could use Stream. Length , it isn't supported for all streams. Using code such as the above, whether synchronously or asynchronously, you shouldn't come across the kinds of error that can otherwise occur, such as data which appears to be corrupted or truncated.

Note that because read here is a long , this code can theoretically cope with files larger than 2GB. In practice I believe all CLR implementations at the time of this writing will choke when asked to create such a large object, but in the future this restriction may be relaxed. Read data, 0, data.

Read buffer, 0, buffer. Read buffer, read, buffer. Copy buffer, newBuffer, buffer.