Problem with select row in list control

tataxin

I have a list control which is declared like this

CListCtrl m_list1;

I set the background color to black, and the text color to white. Whenever I select a row, I just want to draw a rectangular wrap to the row. So I implement the item change method, like this:

void AlarmCompreMsgDig::OnLvnItemchangedList1(NMHDR *pNMHDR, LRESULT *pResult)
{
LPNMLISTVIEW pNMLV = reinterpret_cast(pNMHDR);
m_lstAlarmCompreMsg.SetItemState(-1, 0, LVIS_SELECTED); // first, diselect the row

int rowIndex = pNMLV->iItem;

CRect rec;  // boundary rectangular that wrap the row
m\_lstAlarmCompreMsg.GetItemRect(rowIndex, rec, LVIR\_BOUNDS);


// a little adjust the rectangular
    rec.top -= 2;
rec.bottom += 2;

CDC\* cdc = m\_lstAlarmCompreMsg.GetDC();

CPen aPen;
aPen.CreatePen(PS\_SOLID, 1, RGB(255, 255, 255)); // select color White

CPen\* pOldPen = cdc->SelectObject(&aPen); // Select the pen

// Now draw the rectangular
cdc->Rectangle(rec);

    // select back the old pen
cdc->SelectObject(pOldPen);
    
    \*pResult = 0;

}

That's all. When I select a row, it works. Then I select another row, it works but do not erase the previous rectangular. So my list control is full of rectangular. :(( Does anyone know how to erase the previous rectangular? Thanks in advance, :)

David Crow

When you select an item in a list control, OnLvnItemchangedList1() gets called multiple times. Once for the previous item, and again for the current item. Change the pen color accordingly.

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

tataxin

Thank you for your answer, DavidCrow. Actually, I have a int member of dialog to keep the old row. So this function look like this:

void AlarmCompreMsgDig::OnLvnItemchangedList1(NMHDR *pNMHDR, LRESULT *pResult)
{
LPNMLISTVIEW pNMLV = reinterpret_cast(pNMHDR);
m_lstAlarmCompreMsg.SetItemState(-1, 0, LVIS_SELECTED); // first, diselect the row

int rowIndex = pNMLV->iItem;

CRect rec;  // boundary rectangular that wrap the row
m\_lstAlarmCompreMsg.GetItemRect(rowIndex, rec, LVIR\_BOUNDS);


// a little adjust the rectangular
    rec.top -= 2;
rec.bottom += 2;

CDC\* cdc = m\_lstAlarmCompreMsg.GetDC();

CPen aPen;

    // oldRowIndex is the member of dialog
   if (oldRowIndex == rowIndex){ // this occurs 1st, and 3rd also 
         aPen.CreatePen(PS\_SOLID, 1, RGB(0, 0, 0)); // select color Black (background color)
    } 
    else // this occurs 2nd
    {
         aPen.CreatePen(PS\_SOLID, 1, RGB(255, 255, 255)); // select color White
         oldRowIndex = rowIndex;   // update oldRowIndex
    }        

CPen\* pOldPen = cdc->SelectObject(&aPen); // Select the pen

// Now draw the rectangular
cdc->Rectangle(rec);

    // select back the old pen
cdc->SelectObject(pOldPen);
    
    \*pResult = 0;

}

But there is something wrong here: this function is called 3 time totally. The 1st time it will erase the old rectangular, the second time it draw new rectangular, and then the last time it erase the new created rectangular. I don't know why???

David Crow

tataxin wrote:

But there is something wrong here: this function is called 3 time totally.

Which is correct. The first time you select an item, it should get called once with a new state of LVSI_FOCUSED|LVSI_SELECTED. The next time you select an item, it should get called three times: the first time for the old item to remove the LVSI_FOCUSED style; the second time for the old item to remove the LVSI_SELECTED style; and a third time for the new item with a new state of LVSI_FOCUSED|LVSI_SELECTED. Make sense?

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

tataxin

oh, that's great. I try to find out this, but not success up to now. And, can you explain some more, what should I change in my source code now? I tried some thing but not correct. the structure of pNMLV is

typedef struct tagNMLISTVIEW {
NMHDR hdr;
int iItem;
int iSubItem;
UINT uNewState;
UINT uOldState;
UINT uChanged;
POINT ptAction;
LPARAM lParam;
} NMLISTVIEW, *LPNMLISTVIEW;

which member should I take and how to compare with LVIS_FOCUSED, LVIS_SELECTED? In fact, I tried this

int x = pNMLV->uChanged;
if (x == ){
// draw rectangular here
} else if (x == LVIS_FOCUSED){
// remove old rectangular here
} else if (x == LVIS_SELECTED){
// do nothing
}

but it's always be LVIS_FOCUSED|LVIS_SELECTED, so it always draws and draws

David Crow

tataxin wrote:

int x = pNMLV->uChanged;

Look at the two "state" members.

tataxin wrote:

if (x == ){

You have to compare bits here.

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

tataxin

I solved it, The final source code is;

if ((pNMLV->uChanged & LVIF_STATE) != LVIF_STATE)
return; // state has not changed

if (pNMLV->uOldState & LVIS\_SELECTED)
{
	// remove old rectangular here
}
else if (pNMLV->uNewState & LVIS\_SELECTED)
{
	// draw new rectangular here
}

It works, great!!!!! Thank you for your suggestion, DavidCrow, :)