I have general callback type in C:
typedef int(*OverrideFieldValueSetCB_t)(const char *Dialog, const char *FieldName, void *Value);
and callback:
OverrideFieldValueSetCB_t gOverrideFieldValueSetCB;
and function I call in C-code to pass value to C# :
int DllGuiSetFieldValue(const char *Dialog, const char *FieldName, void *pValue)
{
return gOverrideFieldValueSetCB(Dialog, FieldName, pValue);
}
In C# code I set this kind of delegate:
private static int OverrideFieldValueSetCb(string dialogName, string fieldName, IntPtr value)
{
///...
}
In above I would like to marshal/cast value to int or double depending on fieldName.
Questions:
"Pointing to double or int" is just asking for trouble.
But if you're certain that's the way you want to go, have a look at the Marshal class - Marshal.ReadInt32 for int, and Marshal.PtrToStructure<double> for double. Make sure you don't mess the two up :)
Of course, if you can use unsafe code, you don't need to use Marshal. Just do the cast as you would in C.
Example:
double val = 123.45d;
double second;
double third;
unsafe
{
void* ptr = &val;
second = *(double*)ptr;
third = Marshal.PtrToStructure<double>(new IntPtr(&val));
}
second.Dump();
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