LB_ITEMFROMPOINT  F19ERB 

An application sends this message to retrieve the zero-based index of the item nearest the specified point in a list box.

LB_ITEMFROMPOINT

wParam = 0;                                // not used, must be zero

lParam = (LPARAM) MAKELPARAM(xPos, yPos);  // coordinates of point

Parameters

xPos

Value of the low-order word of lParam. Specifies the x-coordinate of a point, relative to the upper-left corner of the client area of the list box.

yPos

Value of the high-order word of lParam. Specifies the y-coordinate of a point, relative to the upper-left corner of the client area of the list box.

Return Values

The return value contains the index of the nearest item in the low-order word. The high-order word is zero if the specified point is in the client area of the list box, or one if it is outside the client area.