Byte to Integer in c#

Question

I am reading a row from a SQL Server table. One of the columns is of type tinyint.

I want to get the value into an int or int32 variable.

rdr.GetByte(j) 
(byte) rdr.GetValue(j)

...seems to be the only way to retrieve the value. But I can't figure out how to get the result into an int var.

Answer 1

int value = rdr.GetByte(j);

An explicit cast is not required, because a byte to int is a widening conversion (no possibility of data loss).

Answer 2

Casting the byte to int should work just fine:

int myInt = (int) rdr.GetByte(j);

Since C# supports implicit conversions from byte to int, you can alternatively just do this:

int myInt = rdr.GetByte(j);

Which one you choose is a matter of preference (whether you want to document the fact that a cast is taking place or not). Note that you will need the explicit cast if you want to use type inference, or otherwise myInt will have the wrong type:

var myInt = (int) rdr.GetByte(j);

Answer 3

(int)rdr.GetByte(j)

Answer 4

See the documentation for BitConverter.ToInt32 (contains more examples):

byte[] bytes = { 0, 0, 0, 25 };

// If the system architecture is little-endian (that is, little end first),
// reverse the byte array.
if (BitConverter.IsLittleEndian)
    Array.Reverse(bytes);

int i = BitConverter.ToInt32(bytes, 0);
Console.WriteLine("int: {0}", i);
// Output: int: 25

Answer 5

Assigning a byte to an int works:

int myInt = myByte;

But maybe you're getting an exception inside IDataRecord.GetByte, in which case you should check that the index you're using to access the data record really points to a tinyint column. You can check the type returned form GetValue. It should be a byte for a tinyint column.

Trace.Assert(rdr.GetValue(j).GetType() == typeof(byte));

Another option is to forego the fragile numeric index altogether:

int myInt = rdr.GetByte(rdr.GetOrdinal(TheNameOfTheTinyintColumn))