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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
public static final OpCode Brfalse
public static final var Brfalse : OpCode
Not applicable.

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.

Control can only be transferred to the first of these prefixes if the target instruction has one or more prefix codes. 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)

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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