How do I see the value of a DependencyProperty in WinDbg?_问答_开发者

Using WinDbg and trying to debug a Silverlight application for memory leaks, I come across properties on my objects that are implemented as a DependencyProperty - and when I dump the object in the debugger (WinDbg) I can see the property - that is, I can see the actual static field.

How do I开发者_运维百科 see the actual value of the property?

This heavily relies on making assumptions about undocumented internals that may vary in other versions, but by way of example here's how to get the value of the Title property of a window in WPF with .NET 4, documented here so I can find it with Google again.

First, find the address of the value of System.Windows.Window.TitleProperty:

0:000> !name2ee *!System.Windows.Window
...
Module:      54b81000
Assembly:    PresentationFramework.dll
Token:       0200009c
MethodTable: 54f06b54
EEClass:     54ba12bc                          <--- Remember this
Name:        System.Windows.Window
...

0:000> !DumpClass /d 54ba12bc                  <--- EEClass value from above
...
62887fec  40002f1      4cc ...ependencyProperty  0   static 020e724c TitleProperty
...                                                         ^^^^^^^^ Property object address

Now, get its GlobalIndex, which is the bottom 16 bits of the _packedData field:

0:000> !DumpObj /d 020e724c                    <--- Property object address from above
...
62a9c190  4001377       20         System.Int32  1 instance   262372 _packedData
...                                                           ^^^^^^ & 0xffff == 228

So 228 is the GlobalIndex.

Now find the address of the window:

0:000> !name2ee *!Your.Window.Class.Name
...
Module:      00122e9c
Assembly:    YourAssembly.exe
Token:       020001fc
MethodTable: 002a4068                          <--- Remember this
EEClass:     00297504
Name:        Your.Window.Class.Name
...

0:000> !dumpheap -mt  002a4068                 <--- Remember this
 Address       MT     Size
020e6b6c 002a4068      456                     <--- If >1 object found, you must pick the right one.
...

The window is at 020e6b6c. The value you are looking for is somewhere in its _effectiveValues array:

0:000> !DumpObj /d 020e6b6c
...
6288e394  4001359       10 ...ctiveValueEntry[]  0 instance 0912e08c _effectiveValues
...                                                         ^^^^^^^^ Array address

0:000> !DumpArray -details 0912e08c
...
[18] 0912e124
    Name:        System.Windows.EffectiveValueEntry
    MethodTable: 6288978c
    EEClass:     627bda2c
    Size:        16(0x10) bytes
    File:        C:\Windows\Microsoft.Net\assembly\GAC_MSIL\WindowsBase\v4.0_4.0.0.0__31bf3856ad364e35\WindowsBase.dll
    Fields:
              MT    Field   Offset                 Type VT     Attr    Value Name
        57bcf568  40013a7        0            System.Object      0     instance     091df9c8     _value
        57bd4798  40013a8        4             System.Int16      1     instance          228     _propertyIndex
        62a9c360  40013a9        6             System.Int16      1     instance           27     _source
...

The array is sorted by the values of the _propertyIndex fields (except for some empty entries at the end with _propertyIndex == -1) so it is not hard to find the entry with _propertyIndex 228.

Finally, dump the corresponding _value field:

0:000> !DumpObj /d 091df9c8
...
57bcf568  40013c0        4        System.Object  0 instance 020f6228 _baseValue
57bcf568  40013c1        8        System.Object  0 instance 091df92c _expressionValue
57bcf568  40013c2        c        System.Object  0 instance 00000000 _animatedValue
57bcf568  40013c3       10        System.Object  0 instance 00000000 _coercedValue
...

0:000> !DumpObj /d 020f6228                  <--- From _baseValue, gives the binding expression
...
Name:        System.Windows.Data.BindingExpression
...

0:000> !DumpObj /d 091df92c                  <--- From _expressionValue, gives the actual value
...
String:      YOUR WINDOW TITLE
...

Woo hoo.

You should be able to get the value using the GetValue(PropertyName) method on the DependencyObject (which is required for it to have a Dependency Property). Not sure if that works in WinDbg. Tess Ferrandez mentions one tip with Dependency Properties but it doesn't give a true answer.

For a complete solution, try this step-by-step guide: http://georgelache.blogspot.ro/2012/04/steps-to-get-value-of-dependency.html

The example covers the case of obtaining the title of a window

!CLRStack -a

0000000000129270 000006442d6acf50 System.Windows.Window.InternalClose(Boolean, Boolean)

PARAMETERS:

    this (0x0000000000129360) = 0x0000000011b59968

    shutdown = <no data>

    ignoreCancel = <no data>

LOCALS:

    <no data>

    <no data>

    <no data>

...

0:000> !do 0x0000000011b59968

Name: GFW.Controls.View.ShellWindow MethodTable: 00000644805228b8 EEClass: 0000064480516240 Size: 832(0x340) bytes ...

00000644319b3708 40002d3 998 ...ependencyProperty 0 static 00000000115de6d8 TitleProperty 00000644319be898 4001323 20 ...ctiveValueEntry[] 0 instance 00000000154ff638 _effectiveValues ...

0:000> !do /d 00000000115de6d8

Name: System.Windows.DependencyProperty

MethodTable: 00000644319b3708

EEClass: 0000064431857550

Size: 88(0x58) bytes

File: C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\WindowsBase\v4.0_4.0.0.0__31bf3856ad364e35\WindowsBase.dll

Fields:

          MT    Field   Offset                 Type VT     Attr            Value Name

00000644784c6960 400133c 8 System.String 0 instance 00000000111f6450 _name

00000644784c82e8 400133d 10 System.Type 0 instance 0000000011024538 _propertyType

00000644784c82e8 400133e 18 System.Type 0 instance 0000000011255ea8 _ownerType

00000644319b12a8 400133f 20 ....PropertyMetadata 0 instance 00000000115de678 _defaultMetadata

00000644319b1088 4001340 28 ...dateValueCallback 0 instance 00000000115de638 _validateValueCallback

00000644319be750 4001341 30 ...ndencyPropertyKey 0 instance 0000000000000000 _readOnlyKey

0000064431c147f8 4001342 40 System.Int32 1 instance 262462 _packedData

00000644319be408 4001343 48 ....InsertionSortMap 1 instance 00000000115de720 _metadataMap

00000644319b0fc8 4001344 38 ...erceValueCallback 0 instance 0000000000000000 _designerCoerceValueCallback

00000644784c5ab8 400133b 808 System.Object 0 static 000000001102f290 UnsetValue

00000644319bc6c0 4001345 800 ...ty, WindowsBase]] 1 static 0000000021033b88 RegisteredPropertyList

00000644784d1c28 4001346 810 ...ections.Hashtable 0 static 0000000011030aa8 PropertyFromName

00000644784cc848 4001347 5c8 System.Int32 1 static 1290 GlobalIndexCount

00000644784c5ab8 4001348 818 System.Object 0 static 00000000110407e8 Synchronized

00000644784c82e8 4001349 820 System.Type 0 static 0000000011040800 NullableType

GlobalIndex: Get the index of the property: 262462 & 0xFFFF (using Windows Calculator) = 318

!DumpArray -details 00000000154ff638

[31] 00000000154ff838

Name:        System.Windows.EffectiveValueEntry

MethodTable: 00000644319b6120

EEClass:     0000064431858c90

Size:        32(0x20) bytes

File:        C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\WindowsBase\v4.0_4.0.0.0__31bf3856ad364e35\WindowsBase.dll

Fields:

                  MT    Field   Offset                 Type VT     Attr            Value Name

    00000644784c5ab8  400136e        0            System.Object      0     instance     0000000041dd7b88     _value

    00000644784d0930  400136f        8             System.Int16      1     instance                  318     _propertyIndex

    0000064431c149b0  4001370        a             System.Int16      1     instance                   11     _source

0:000> !do /d 0000000041dd7b88

Name: System.String

MethodTable: 00000644784c6960

EEClass: 000006447804eec8

Size: 108(0x6c) bytes

File: C:\WINDOWS\Microsoft.Net\assembly\GAC_64\mscorlib\v4.0_4.0.0.0__b77a5c561934e089\mscorlib.dll

String: My Window Title