IDebugExpression2
This interface represents a parsed expression ready for binding and evaluating.
IDebugExpression2 : IUnknown
Notes for Implementers
The debug engine (DE) implements this interface to represent a parsed expression ready to be evaluated.
Notes for Callers
A call to IDebugExpressionContext2::ParseText returns this interface. IDebugStackFrame2::GetExpressionContext returns the IDebugExpressionContext2 interface. These interfaces are accessible only when the program being debugged has been paused and a stack frame is available.
Methods in Vtable Order
The following table shows the methods of IDebugExpression2.
Method |
Description |
|---|---|
Evaluates this expression asynchronously. |
|
Ends asynchronous expression evaluation. |
|
Evaluates this expression synchronously. |
Remarks
When a program has halted, the session debug manager (SDM) obtains a stack frame from the DE with a call to IDebugThread2::EnumFrameInfo. The SDM then calls IDebugStackFrame2::GetExpressionContext to get the IDebugExpressionContext2 interface. This is followed by a call to IDebugExpressionContext2::ParseText to create the IDebugExpression2 interface, which represents the parsed expression ready to be evaluated.
The SDM calls either IDebugExpression2::EvaluateSync or IDebugExpression2::EvaluateAsync to actually evaluate the expression and produce a value.
In an implementation of IDebugExpressionContext2::ParseText, the DE uses COM's CoCreateInstance function to instantiate an expression evaluator and get an IDebugExpressionEvaluator interface (see the Example in the IDebugExpressionEvaluator interface). The DE then calls IDebugExpressionEvaluator::Parse to obtain an IDebugParsedExpression interface. This interface is used in the implementation of IDebugExpression2::EvaluateSync and IDebugExpression2::EvaluateAsync to perform the evaluation.
Requirements
Header: msdbg.h
Namespace: Microsoft.VisualStudio.Debugger.Interop
Assembly: Microsoft.VisualStudio.Debugger.Interop.dll
See Also
Reference
IDebugExpressionEvaluationCompleteEvent2::GetExpression