OpCodes.Brfalse Field

 

Transfers control to a target instruction if value is false, a null reference (Nothing in Visual Basic), or zero.

Namespace:   System.Reflection.Emit
Assembly:  mscorlib (in mscorlib.dll)

public static readonly OpCode Brfalse

The following table lists the instruction's hexadecimal and Microsoft Intermediate Language (MSIL) assembly format, along with a brief reference summary:

Format

Assembly Format

Description

39 < int32 >

brfalse target

brnull target

brzero target

Branches to a target instruction at the specified offset if false.

The stack transitional behavior, in sequential order, is:

  1. value is pushed onto the stack by a previous operation.

  2. value is popped from the stack; if value is false, branch to target.

The brfalse instruction (and its aliases brnull and brzero) transfers control to the specified target instruction if value (of type int32, int64, object reference O, managed pointer &, transient pointer *, native int) is zero (false). If value is non-zero (true) execution continues at the next instruction.

The target instruction is represented as a 4-byte signed offset from the beginning of the instruction following the current instruction.

If the target instruction has one or more prefix codes, control can only be transferred to the first of these prefixes. Control transfers into and out of try, catch, filter, and finally blocks cannot be performed by this instruction.

The following Emit method overload can use the brfalse opcode:

  • ILGenerator.Emit(OpCode, Label)

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.1
Windows Phone
Available since 8.1
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