question about subnetmask

is there any method in C# to which i pass ip address and subnetmask and it return true if given ip is in subnet mask?

For example, i give ip 192.168.0.149 and subnetmask 192.168.0.0 to the funtion and it return true................... Is there some thing like this in C#

If you have the IP (v4) address stored in a long....

Code:

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bool match = (addr & mask) == mask;

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If you have it in a byte array..

Code:

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bool match = (addr[0] & mask[0]) == mask[0]) &&
                    (addr[1] & mask[1]) == mask[1]) &&
                    (addr[2] & mask[2]) == mask[2]) &&
                    (addr[3] & mask[3]) == mask[3]);

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If you have it in a string.... DONT! Change your design. :p