Move A Form With No Title Bar/Resize Controls

This sample shows 2 ways to move a form that has no title bar. All that is visible is the body or client area of the form. It also shows how to resize a control by dragging its edge.

The first method of moving a form is a bit more cumbersome but illustrates one possibility. By detecting the cursor location in the form's MouseDown event and comparing it to its position in the MouseUp event we can determine if the form should be moved and where to move it to. Then using the SetWindowPlacement API we can move the form to the new location. GetCursorPos is used to get the current position of the cursor on the screen.

The second method uses the ReleaseCapure and SendMessage APIs and is very concise requiring only 2 lines of code. These are the same APIs that let you resize a control by dragging one of its edges just like you resize a window.

Download Source Code

To create a form without a title bar set the following properties:

   Caption = ""
   ControlBox = False

This method uses two main APIs. The GetCursorPos function to see where the form is and the SetWindowPlacement function to move the form to the new location. GetCursorPos uses a PointApi structure which contains elements for the x and y coordinates of the cursor. SetWindowPlacement uses a WindowPlacement structure which uses the PointApi as well as Rect structures as sub elements.

We start with the form load event which sets the WindowPlacement structure's .Length property to the size of the structure and its .ShowCmd property to SW_SHOWNORMAL. This is the action we want to take when we move the form.

In the form's MouseDown event a call is made to GetCursorPos. This retrieves the location of the mouse when it is pressed and saves it in a set of global variables.

When the mouse is released, the form's MouseUp event triggers. Another call to GetCursorPos is made to get the new coordinates of the cursor. If the old and new values are the same, plus or minus a few pixels, the form has not been moved. When they differ, the new location of the form is set. This is done by setting the values of the .rcNormalPosition property of the WindowPlacement structure. This element is of type Rect meaning it can contain the coordinates of the four corners of the form. Once the new location of the form is set, SetWindowPlacement is called to move the form to its new spot.

Using the ReleaseCapture and SendMessage functions only requires 2 lines of code (not counting the API declares).

   Call ReleaseCapture
   Call SendMessage(hwnd, WM_NCLBUTTONDOWN, HTCAPTION, 0&)

Download the source and run it. Move the cursor anywhere on the form, except over the Quit button or the labels, and press the left mouse button. Move the cursor to a new location and release the mouse button. The form will move to the new location. Now click on the Hand and move the form. Release the mouse to stop moving the form. Drag the left or right edge of the center button to resize it.