obtaining listview data efficiently...

hey all,
I am currently writing a function to obtain all of a listview control's data and store it into a multidimensional array of pointers. the reason for this is simply because it makes it easier for me to access each string of listview data.

I have a listview (LVS_REPORT) with 4 columns. here is how I am declaring my multidimensional array of pointers:

Code:

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char *szListData[50][4];

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where 50 is the max number of rows, and 4 is the number of columns. now here is how I am attempting to obtain the data:

Code:

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for(i = 0; i < nListNum; i++)
    for(j = 0; j < 4; j++)
        ListView_GetItemText(hwndList, i, j, szListData[i][j], _MAX_FNAME);

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what am I doing wrong here? nListNum is the number of items listed in the listview, which is a number less than or equal to 50.

whenever I attempt to print anything from szListData (just to see if it worked), Windows throws up an error message saying that the application needs to be closed.

could anyone please tell me what I am doing wrong here?

any help is greatly appreciated :) .

It is a multidimensional array which has 50 "rows".
Now, it has 4 "columns". And every column contains... unallocated memory or.... a single character?
Wouldn't this make more sense:

Code:

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char szListData[50][4][_MAX_FNAME];

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thanks max, I was using an array of pointers because I figured that way I could only allocate the size of each piece of data (without having to set a size to be allocated), but doing it that way would involve some complex allocation routine (getting the length of each piece of data and allocating each pointer by that). when I change this:

Code:

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char *szListData[50][4];

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to this:

Code:

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char szListData[50][4][_MAX_FNAME];

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my little bit of debug code to print from the array prints just how I wanted :) .

Quote:

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Originally Posted by sl34k

but doing it that way would involve some complex allocation routine (getting the length of each piece of data and allocating each pointer by that).

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You wouldn't really need a complex allocation routine, just one where you had a large buffer, then strdup() the string to the location in the array. Just don't forget to free() the array elements if you reassign (and before you return).

thanks Kennedy, but doing it with an array seems to work fine, I just looked at the decription of strdup, and I can't really be bothered doing it that way :rolleyes: .

but I have ran into another pointer related problem :rolleyes: .

I am starting to understand pointers alot better now, all this experience is surely helping. here is what I am doing:

Code:

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p = PathFindFileName(szListData[0][0]);

strcpy(pfile->name, p);

MessageBox(NULL, pfile->name, NULL, MB_OK);

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when I compile, it compiles 0 errors, 0 warnings, but when I run it, I get the error from Windows saying that the application needs to be closed.

p is declared:

Code:

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char *p = "";

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name is declared:

Code:

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char name[_MAX_FNAME];

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when I try this:

Code:

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p = PathFindFileName(szListData[0][0]);

MessageBox(NULL, p, NULL, MB_OK);

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it prints the filename successfully without any problems.

can anyone please tell me why this is happening here? I really can't figure this one out, name is an array that obviously has _MAX_FNAME bytes allocated. :confused: