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Product
- Key Features
- Introduction
- Manual
- Read At First
- Data Type
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- Function & Parameter
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- The Workspace
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Windows
Form- EPL Library
- Embedded Data Base
- Windows Dll & APIs
- Using ActiveX & TypeLib
- Debugging
- Compile & Release
- Develop DLL
- Linux
- System Requirements
- Screenshot
Windows Form
The EPL will add a form named “_MainForm” automatically to your application when you create a new Windows Form Application. The EPL Windows Form provides most common programming elements for windows GUI application, it contains properties, methods and events.
To add a new form, you can click “Insert” -> “Form” menu. And the name of new adding form will be auto-named.
Form Basic Property
The basic property of form/control is provided by EPL system, not by the form/control themselves. In the form/control properties list, the basic properties are showed in top of the list, the self-provided properties of form/control are showed in the bottom, they separate with a bold line. The main difference between basic and self-provided property is the basic property will be valid before the form/control is created, but self-provided properties won’t.
| Property Name | Description |
|---|---|
| Left | Specifies the location of the left edge of the form |
| Top | Specifies the location of the top edge of the form |
| Width | Specifies the width of form, in pixels units |
| Height | Specifies the height of form, in pixels units |
| Tag | Specifies extra string type value for form or program |
| Visible | Specifies the visibility of a form |
| Disable | Specifies whether the form is disabled |
| MousePointer | Specifies the mouse pointer for the form |
| Focus | Sets whether the focus can stay on this form/control when user use Tab key or cursor switch the inputting focus |
| TabOrder | This property is only valid when “Focus” property is True. It’s the order that user switch the inputting focus by Tab key or cursor. When the form is loaded, inputting focus will switch to the control that has the minimal TabOrder |
Form Basic Events
“System Basic-Events” & “Control Self-Events”
“System Basic-Events” is provided by the system, all the form controls has these events. In list below will mark as type of “Basic”
“Control Self-Events” is provided by specified control itself. In list below will mark as type of “Self”
| Events Name | Events Name | Type |
|---|---|---|
| LButtonDown | Occurs this event when the user presses the left mouse button while the cursor is on the form | Basic |
| LButtonUp | Occurs this event when the user releases the left mouse button while the cursor is on the form | Basic |
| DblClick | Occurs when the user presses and releases a mouse button and then presses and releases it again on the form | Basic |
| RButtonDown | Occur this event when the user presses the right mouse button while the cursor is on the form | Basic |
| RButtonUp | Occurs this event when the user releases the right mouse button while the cursor is on the form | Basic |
| MouseMove | Occurs when the user moves the mouse on the form | Basic |
| GetFocus | Occurs this event when object got inputting focus | Basic |
| LostFocus | Occurs this event when the object losts the focus | Basic |
| KeyDown | Occurs this event when user presses a key | Basic |
| KeyUp | Occurs this event when the user releases a key that previously pressed | Basic |
| KeyPress | Occurs this event when user presses or releases a character key | Basic |
| MouseWheel | Occurs this event when user scrolls mouse wheel | Basic |
| AfterCreate | Occurs this event when all the controls has been created before displaying | Self |
| BeforeClose | Occurs this event before close the form. Returns False if doesn't allow to close, returns True or returns nothing if allow to close | Self |
| BeforeDestroy | Occurs this event before destroy this window. All the controls will be disable after destroy | Self |
| Move | Occurs this event when the position of window has been changed | Self |
| Size | Occurs this event when the size of form has been changed | Self |
| Activate | Occurs this event when the state of the window has been change to be active | Self |
| Deactivate | Occurs this event when the state of the window has been change to be deactivated | Self |
| Idle | Occurs this event when system is in idle state, user can do some processing for background. Returns False or returns nothing to disable this event to occur again. Returns True to enable to occur this event again | Self |
| FirstActivate | Occurs this event when first time to be active | Self |
| TrayEvent | Occurs this event when the try icon set by this form received mouse click event | Self |
| Show | Occurs this event when the form is displayed | Self |
| Hide | Occurs this event when hide form | Self |
LButtonDown
LButtonUp
DblClick
RButtonDown
RButtonUp
MouseMove
The parameters of the events (LButtonDown, LButtonUp, DblClick, RButtonDown, RButtonUp, MouseMove) are
x: Indicates the Horizontal position of the mouse pointer in control coordinates
y: Indicates the vertical position of the mouse pointer in control coordinates
FunctionKeyState: Used to check determine whether each key is down. Can be one of the following constants or their summation: 1,#CtrlKey; 2,#ShiftKey; 4,#AltKey. Use "And" command to check specified key is down. Means specified key is down if return nonzero value
KeyDown
KeyUp
The parameters of the events (KeyDown, KeyUp) are
KeyCode: Key constants, like: "F1Key", "EnterKey" etc. Check constants list of library to retrieve value of specified key
FunctionKeyState: Same as previous.
The events (LButtonDown, LButtonUp, DblClick, RButtonDown, RButtonUp, MouseMove, KeyDown, KeyUp) should return a Boolean type value. If returns False, just cancel this event, and doesn’t post the event the event-container any more; if returns True or not return, post this event to the event-container that the event belongs to.
GetFocus
LostFocus
KeyPress
Character keys includes all the printable characters, Enter and Backspace. If returns False, this event is canceled; the event is passed if returns True or does not return. The CharCode event parameter indicates corresponding character code of key with down state, retrieves specified character by "Chr" function
MouseWheel
Form Method
| Method Name | Description |
|---|---|
| GetHWnd | Returns a handle to a form or a control, the handle is just Win32 HWND |
| Destroy | Destroys this form and all controls on this from. Loads the form again to use if the form has been destroyed |
| SetFocus | Moves the focus to this form or control. For a form, the focus will move to the first control that can accept focus |
| HasFocus | Indicates whether the control has the focus |
| GetClientWidth | Returns the width of client area, in pixels units. For a form, the client area is the entire area of the window excludes title bar, menu bar, frames. For a control, its client area is equal to its entire area |
| GetClientHeight | Returns the height of client area, in pixels units. For a form, the client area is the entire area of the window excludes title bar, menu bar, frames. For a control, its client area is equal to its entire area |
| DisableRedraw | Disables the redraw operation of a Form or control to avoid flicker. "EnableRedraw" can be called to resume |
| Redraw | Notifies the Windows system that the entire area of this Form or Control need to be redrawed |
| RedrawRect | Notifies the Windows system that the specified rectangle of this Form or Control needs to be redrawed |
| CancelRedraw | Notifies the Windows system that this Form or Control does not need to be redrawn, all its display content will be reserved |
| Refresh | Redraws if displaying content of this from or control need to redraw, otherwise returns immediately |
| Move | Changes the position or size of a Form or Control |
| Zorder | Changes the layer of a Form or Control |
| PopupMenu | Displays the menu at the specified position or the current mouse position. Automatically use its container form if called object is window control |
| SendMessage | Sends the specified message to a window or control. It calls the window procedure for the specified window and does not returns until the window procedure has processed the message |
| PostMessage | Places (posts) a message in the message queue associated with the thread that created the specified window and returns without waiting for the thread to process the message |
| GetTagControl | Returns the control that contains the specified numerical string in the current Window Form. An runtime occurs if doesn't exist |
| SetShapePicture | Sets the shape of the form with the picture, Note: the picture format can't be icon or cursor. The contour of the picture should be as solid as possible, that can make the refreshing speed of the Window Form faster. Returns True if succeeds, otherwise returns False |
| Activate | Activate a form |
| SetTrayIcon | Sets an icon that indicated this program to system tray |
| PopupTrayMenu | Pops up menu in the current mouse position, this function is for popuping system tray icon menu |
| SetParent | Sets specified form or form control as parent form of this object |
Add/Delete Form
To add a new form to application, you can click “Insert” ->”Form” menu. See picture below
GetFocus
To delete a form, you can activate the Application tab of Workspace tabs, and right-click to activate the form item you want to delete and popups a menu, finally click “Delete Form” on the menu
Load/Destroy Form
All the forms must load by “Load()” function, except the form “_MainForm” that set to automatically load as starting mode. After a form is loaded, all the property of form changed will be restored to original designing status after destroy it. But if the property of form or control is static, the changed property won’t be restored, and keep it always.
All the loaded forms must be destroyed if you don’t need it anymore. To destroy, you can call “Destroy” method of form.
Menu
Add/Edit Menu
To add menus to a form, you can use the Menu Editor. First activate a from when design and click “Tools” ->”Menu Editor” menu or directly press “Ctrl + E” keys.
To add new menu items, you can click “Insert Before” or “Insert After” button.
To change menu items’ layer, you can click “Move Left” or “Move Right” button.
To change menu items’ position, you can click “Move Up” or “Move Down” button.
Hot Key & Shortcut Key
To set a Hot Key to a menu item, you just click on a menu item, and add a “&” mark before the word that you want to set as hot key.
To set a Shortcut Key to a menu item, you just click on a menu item, and choose a key in “Shortcut” drop down list. See picture below
Checked
Use this attribute, you can set a menu item to be checked or not. The checked menu item will appear as a √ mark.
Enabled
Use this attribute, you can enable or disable a menu item, the disabled menu item will appear in gray color, and can’t be operated.
Visible
Use this attribute, you can show or hide a menu item.
Receive Click Event
All the non-top level menu items can receive a Click event.
Control The Menu
You can also write code to control the menu, all the menu items have the name you pre-named in Menu Editor, you just use the name and a “.” mark to operate every properties of the menu item, such as if the “mnuSave” is the name of a menu item, you can call
mnuSave.Visible = False
to hide the menu item
Popup Menu
You can call “PopupMenu” function to display the menu at the specified position or the current mouse position. Automatically use its container form if called object is window control.
Notice that, don’t forget click OK button to confirm all the changing of the menu after you finish to edit menu, otherwise all the changing will be discarded.
MsgBox & InputBox
The MsgBox() and InputBox() function are very common used functions, actually the MsgBox() is just like Windows API MessageBox().
MsgBox function
MsgBox (All Prompt, Integer CommandButton, [String Caption])
The MsgBox function shows a message box. The return value indicates which button is pressed. 0,#OK; 1,#Cancel; 2,#Abort; 3#Retry; 4,#Ignore; 5,#Yes; 6,#No. ESC key has the same effect with Cancel button.
The following describes parameters of this function
| Parameter | Type | Description |
|---|---|---|
| GetHWnd | All | This parameter can be only String, Number, Boolean or DateTime. If the prompt contains multi-lines of texts, you can use carriage return character (Chr(13), Chr(10) or (Chr13) + Chr(10)) to separate each lines |
| CommandButton | Integer | This parameter can be a combination of constants
of the following groups of constants. Only one value can be used
from one group (except group 5): Group 1 (Buttons): 0,#ButtonOK; 1,#ButtonOKCancel; 2,#ButtonAbortRetryIgnore; 3,#ButtonCancelYesNo; 4,#ButtonYesNo; 5,#ButtonRetryCancel Group 2 (Icons): 16,#IconError;32,#IconQuestion;48,#IconWarning; 64,#IconInformation Group 3 (Default button): 0,#DefaultButton1; 256,#DefaultButton2; 512,#DefaultButton3; 768,#DefaultButton4 Group 4 (Modal): 0,#TaskModal; 4096,#SystemModal Group 5(Others): 65536, #TopMost; 524288,#RightAlign |
| Caption | All | This parameter can be ignored. Specifies the caption of the dialog. The default caption is "Information". |
InputBox function
InputBox ([String Prompt],[String Caption],[String InitString],All Buffer,[Integer InputMode])
The InputBox function displays an input dialog to receive the input of user. Returns True if OK button(or Enter key) is pressed, otherwise False.
The following describes parameters of this function,
| Parameter | Type | Description |
|---|---|---|
| Prompt | String | If the prompt contains multi-lines of texts, you can use carriage return character (Chr(13), Chr(10) or (Chr13) + Chr(10)) to separate each lines. If the string is too long or has too much lines, possibly the contents can't display completely |
| Caption | String | This parameter can be ignored. Specifies the caption of the dialog. The default caption is "Please input". |
| InitString | String | Specifies the initial content of the TextBox |
| Buffer | All | Only variable is accepted. The parameter can be Number or String type to retrieve input-data of different types |
| InputMode | Integer | This parameter can be ignored. Can be one of the following constants: 1,#InputString; 2,#InputInteger; 3,#InputDouble; 4,#InputPassword. The default value is #String |