VB Decompiler Plugin API

This documentation describes the interface for creating plugins for VB Decompiler. The plugin system allows you to analyze, modify, or extend the decompiled code and internal structures of the application via a shared library (DLL).
1. Architecture Overview
The plugin system operates on a callback model:
  • VB Decompiler loads your DLL plugin.
  • It calls your exported functions to retrieve the plugin name and author info.
  • It calls VBDecompilerPluginLoad, passing a pointer to its internal Callback Engine.
  • Your plugin interacts with the host by calling this Engine function using specific Action IDs (vlType constants).
2. Exported Functions
Your DLL must export the following stdcall functions:
VBDecompilerPluginName
Called by the host to retrieve the display name of your plugin.
void __stdcall VBDecompilerPluginName( HWND VBDecompilerHWND, // Handle to main window HWND RichTextBoxHWND, // Handle to the code editor window char* Buffer, // Target buffer (100 bytes, ANSI) int Reserved // Reserved );
Usage: Copy a standard ASCII string (max 100 chars) with your plugin name into Buffer.
VBDecompilerPluginAuthor
Called to retrieve author contact information.
void __stdcall VBDecompilerPluginAuthor( HWND VBDecompilerHWND, HWND RichTextBoxHWND, char* Buffer, // Target buffer (ANSI) int Reserved );
Usage: Copy a string like "Author Name, email@domain.com" into Buffer.
VBDecompilerPluginLoad
The main entry point where your plugin logic is executed.
void __stdcall VBDecompilerPluginLoad( HWND VBDecompilerHWND, HWND RichTextBoxHWND, char* Buffer, // Reserved/Buffer void* PluginEngine // <--- Pointer to the Callback Function );
Usage: Store the PluginEngine pointer. You will use it to invoke GetValue / SetValue commands (see "Callback Engine" below).
3. The Callback Engine
Communication with VB Decompiler is handled via a single callback function pointer provided in PluginEngine.
Function Signature:
typedef wchar_t* (__stdcall *TVBDPluginEngine)( int vlType, // Command ID (Action) int vlNumber, // Primary Index (Form/Module ID) int vlFnNumber, // Secondary Index (Function ID) char* vlNewValue // Value to set (ANSI string) or NULL for Get commands );
Note: The engine accepts ANSI strings (char*) for inputs but returns Unicode strings (wchar_t*) for results.
4. Command Reference (vlType)
The following constants are used as the vlType argument to perform specific actions.
Global Project Commands
Operations related to the project file or global settings. vlNumber and vlFnNumber are usually 0.
ID
Constant
Description
1
GetVBProject
Get the full text of the decompiled project file.
2
SetVBProject
Replace the project file content.
3
GetFileName
Get the full path of the file being analyzed. (v3.5+)
4
IsNativeCompilation
Returns "1" if the target is compiled to Native Code, "0" for P-Code. (v3.5+)
5
ClearAllBuffers
Clears internal decompiler structures. Use this if your plugin implements a full custom decompiler for a new language. (v3.9+)
6
GetCompiler
Returns compiler type: 1=VB, 2=.NET, 3=Delphi, 4=Unknown. (v3.9+)
7
IsPacked
Returns "1" if the file is packed/compressed, "0" otherwise. (v3.9+)
56
GetVBDecompilerPath
Returns the path to the VB Decompiler executable. (v3.5+)
100
UpdateAll
Commit changes and refresh the GUI. Required after setting values to ensure the user sees changes.
UI Control
Control elements of the VB Decompiler interface.
ID
Constant
Description
8
SetStackCheckBoxValue
Set Parse stack parameters checkbox state. "1" = Checked, "0" = Unchecked. (v3.9+)
9
SetAnalyzerCheckBoxValue
Set Procedure analyzer and optimizer checkbox state. "1" = Checked, "0" = Unchecked. (v3.9+)
50
GetActiveText
Get text currently displayed in the active code window.
51
SetActiveText
Set text in the active code window.
52
GetActiveDisasmText
Get the raw disassembly text of the disassembler window. (v9.4+)
53
SetActiveDisasmText
Set the raw disassembly text to the disassembler window. (v9.4+)
54
SetActiveTextLine
Scroll or jump to a specific line number (passed as string in vlNewValue).
55
GetActiveModuleCoordinats
Get IDs of the active view. Likely returns format "ModuleIndex,FunctionIndex". (v3.5+)
58
SetStatusBarText
Display a custom message in the application status bar. (v3.5+)
Forms
Operations on VB Forms. vlNumber: Form Index (0-based).
ID
Constant
Description
10
GetVBFormName
Get the name of the form.
11
SetVBFormName
Rename the form.
12
GetVBForm
Get the decompiled properties of the form.
13
SetVBForm
Set the properties of the form.
14
GetVBFormCount
Returns total number of forms in the project.
Modules
Operations on Standard Modules (.bas) or Class Modules (.cls). vlNumber: Module Index (0-based).
ID
Constant
Description
30
GetModuleName
Get the name of the module.
31
SetModuleName
Rename the module.
32
GetModule
Get the decompiled declarations header of the module.
33
SetModule
Set the decompiled declarations header of the module.
34
GetModuleStringReferences
Get list of string references used in this module.
35
SetModuleStringReferences
Set string references.
36
GetModuleCount
Returns total number of modules.
Procedures / Functions
Operations on specific functions within a module.
vlNumber: Module Index.
vlFnNumber: Function Index (0-based) within that module.
ID
Constant
Description
20
GetSubMain
Get the code for the entry point (Sub Main). (Index args ignored).
21
SetSubMain
Set the code for the entry point.
40
GetModuleFunctionName
Get the name of a specific function.
41
SetModuleFunctionName
Rename the function.
42
GetModuleFunctionAddress
Get the memory address (VA) of the function.
43
SetModuleFunctionAddress
Set the function address.
44
GetModuleFunction
Get the decompiled code of the function.
45
SetModuleFunction
Set the code of the function.
46
GetModuleFunctionStrRef
Get string references specific to this function.
47
SetModuleFunctionStrRef
Set string references for this function.
48
GetModuleFunctionCount
Returns number of functions in the specified module.
57
GetModuleFunctionCode
Get function code in "Fast Decompilation" mode (if this function is not processed at this time). (v3.5+)
70
GetModuleFunctionDisasm
Get the disassembly (ASM) of the function. (v9.4+)
71
SetModuleFunctionDisasm
Set the disassembly of the function. (v9.4+)
Resources (FRX)
Access to binary form resources (icons/images). vlNumber: Icon Index.
ID
Constant
Description
60
GetFrxIconCount
Returns total number of icons/images in FRX. (v5.0+)
61
GetFrxIconOffset
Get the file offset for the specific icon. (v5.0+)
62
GetFrxIconSize
Get the size (in bytes) of the specific icon. (v5.0+)
Want to create your own plugin? Look at Plugin Developer Guide and Download the Plugin SDK

VB Decompiler Plugin SDK on GitHub