- 1 year ago
How can I connect 2 text boxes with a line in Win32?
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To connect two text boxes with a line in a Win32 application, you can create a custom control that handles the drawing of the line between the text boxes. Here's an example of how you can achieve this:
Create a custom control:
- Define a custom control class that inherits from
Window
orStatic
(depending on your requirements) in your Win32 application. - Override the
WM_PAINT
message handler to perform the drawing of the line between the text boxes. - Register the custom control class using
RegisterClass
orRegisterClassEx
.
- Define a custom control class that inherits from
Position the text boxes:
- Position the two text boxes on your main application window using appropriate coordinates and sizing.
Draw the line:
- In the custom control's
WM_PAINT
message handler, use theBeginPaint
andEndPaint
functions to obtain the device context (HDC
) for drawing. - Use the
MoveToEx
andLineTo
functions to draw a line between the two text boxes. Specify the starting and ending coordinates for the line using the text box positions.
- In the custom control's
Handle text box movement or resizing:
- To ensure that the line remains connected to the text boxes when they are moved or resized, handle the appropriate messages (e.g.,
WM_MOVE
,WM_SIZE
) for the text boxes. - Update the line's coordinates accordingly and trigger a redraw of the custom control.
- To ensure that the line remains connected to the text boxes when they are moved or resized, handle the appropriate messages (e.g.,
Here's a simplified example of the custom control class:
cppLRESULT CALLBACK CustomControlProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// Draw line between text boxes
HPEN hPen = CreatePen(PS_SOLID, 1, RGB(0, 0, 0)); // Set the line color and style as needed
HPEN hOldPen = SelectObject(hdc, hPen);
// Get text box coordinates and draw the line
// Example: Draw line from (x1, y1) to (x2, y2)
MoveToEx(hdc, x1, y1, NULL);
LineTo(hdc, x2, y2);
SelectObject(hdc, hOldPen);
DeleteObject(hPen);
EndPaint(hWnd, &ps);
return 0;
}
// Handle other messages as needed
}
return DefWindowProc(hWnd, message, wParam, lParam);
}
void RegisterCustomControl(HINSTANCE hInstance)
{
WNDCLASS wc = {};
wc.lpfnWndProc = CustomControlProc;
wc.hInstance = hInstance;
wc.lpszClassName = L"CustomControl";
RegisterClass(&wc);
}
You would need to handle the specifics of positioning the text boxes and updating the line coordinates when the text boxes are moved or resized.
By implementing this custom control and handling the appropriate messages, you can connect the two text boxes with a line in your Win32 application.