Using resources from a DLL

Using Resources from DLL

Requirements:
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Let us consider we have a DLL named 'FilingResource.DLL' containing resource of Dialog having ID as IDD_NETWORK_PATH_SETUP. We have class CFilingResourceDlg associated with this dialog. We want to import this dialog in the DLL, in our program by inheriting CFilingResourceDlg class with the class CDerivedClass.

Steps to use Resource stored in DLL:
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1) Load the DLL using LoadLibrary()
The LoadLibrary function maps the specified executable module into the address space of the calling process. LoadLibrary takes one parameter of LPCTSTR type which points to the null terminated string that names the executable module i.e. the name of the DLL. If the function succeeds, the return value is a handle to the module (DLL in our case).
e.g. HINSTANCE hResourceDLL = ::LoadLibrary(_T(“FilingResource.DLL”));

2) Convert the dialog ID, which is an integer, to resource type so that it can be used with resource related functions.
e.g. LPCTSTR lpszTemplateName =
MAKEINTRESOURCE(IDD_NETWORK_PATH_SETUP);

3) Determine the Resource (i.e. Dialog) in the module (i.e. DLL) using FindResource()
The FindResource function determines the location of a resource (Dialog in our case) with the specified type and name in the specified module (DLL in our case). FindResource() takes three parameters: A Handle to the module, Name of the resource and type of the resource. If the function succeeds, the return value is a handle to the specified resource’s info block.
e.g HRSRC hResource = ::FindResource(hResourceDLL, lpszTemplateName, RT_DIALOG);

4) Load the Resource using LoadResource.
The LoadResource function loads the specified resource into global memory. This function takes two parameters: A handle to the executable module and the resource found using FindResource. If the function succeeds, the return value is a handle to the global memory block containing the data associated with the resource. If it fails, the return value is NULL.
e.g. HGLOBAL hTemplate = LoadResource(hResourceDLL, hResource);

5) Lock the resource in memory using LockResource.
The LockResource function locks the specified resource in memory. This function takes the handle of the resource obtained by LoadResource as a parameter. If the loaded resource is locked, the return value is a pointer to the first byte of the resource; otherwise, it is NULL.
e.g. LPDLGTEMPLATE lpDialogTemplate = (LPDLGTEMPLATE)LockResource(hTemplate);

6) Create object of the class and call InitModalIndirect() and DoModal() of the Dialog.
The empty constructor is called to construct the dialog-box object. Next, InitModalIndirect is called to store the handle to the in-memory dialog-box template. The Windows dialog box is created and displayed later, when the DoModal member function is called.
e.g
CDerivedClass derivedClassObj;
derivedClassObj.InitModalIndirect(lpDialogTemplate);
derivedClassObj.DoModal();


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