So I created a simple subclass to answer a question on the RB Forum and made the mistake of saying I would write a simple description of how I did it.
Some of the detail of these instructions is influenced by the fact that I created it in the Windows IDE.
The sample project is on my website.
In the Project tab of a new project, I created a new class and set its Name to sjgTextBox and its Super to Canvas.
I double-clicked the new sjgTextBox class and in the tab that opened, I created a few properties to store the text details and the mouseDown position.
- BorderColour and TextColour are public Color properties with default values.
- When setting Text, I need to change the width of the control appropriately, so I created a computed property.
- Private properties mDownX and mDownY as Integer will come in handy for remembering where the mouseDown occurred, when dragging.
In the
setter for
Text, I added code to resize the control based on the string width plus blank space the size of "W" at each end.
In the
Paint event, I added code to draw a border around the control and the text property inside it.
In the
mouseDown event, I added code to record the position of the mouse on the parent window.
In the
mouseDrag event, I check whether the control is already positioned according to the mouse and, if not, I move it to the correct position on the parent window.
Going back to the
Project tab, I right-clicked the
sjgTextBox class and selected "Property List Behavior...", where I checked the three public properties I had created, so they would appear in the control's property-list.
The control was now complete, so the next job was to add some to a window.
I opened the window's code view and in the popupmenu above the control palette on the left, I selected "
Project controls" and dragged 3
sjgTextBoxes onto the Window.
For each I set its Text property and the two Colour properties.
Compile and test.
