zxing qr code encoder example c# OnKey Method in C#

Painting QR Code in C# OnKey Method

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The OnKey method allows you to create hotkeys that will run a particular routine when pressed or block Excel from behaving normally when the key combination is pressed. The syntax for the OnKey method is

Application.OnKey(Key, Prodecure)

Microsoft Office Excel 2003 Programming Inside Out Key is a string value representing the key combination to be assigned; see Table 6-3 for a list of special key codes. Procedure is a string value representing the name of the procedure to be invoked. If Procedure is blank (that is, the parameter is set to the empty string by assigning it the value " "), the key combination performs no action, even if Excel normally reacts to the key combination. If the Procedure argument is omitted entirely (that is, there is nothing after the comma), the key combination is reset to normal, default actions. You can combine a key with one or more of the key modifiers (Shift, Ctrl, and/or Alt) to create key combinations as needed. The following example runs a procedure when Alt+H is pressed:

Application.OnKey "%h", "MyProcedure"

The following example takes the key combination that normally opens the Excel Find and Replace (Ctrl+H) dialog box and uses it to invoke a custom procedure:

Application.OnKey "^h", "MyProcedure"

Application.OnKey "^h", ""

This last example resets Ctrl+H to the default action in Excel (Find and Replace).

Application.OnKey "^h"

The most common usage of the OnKey method would be to set hot keys when a workbook is opened or closed. This allows the workbook to provide hot keys that are specific to the workbook and resets the keys to their default values when closed. The two following procedures, when placed inside the Y2001ByMonth.xls file, assign the hot key of Alt+C to the CopySheet procedure to add a new worksheet to the workbook:

Sub Auto_Open() Application.OnKey "%c", "CopySheet" End Sub Sub Auto_Exit() Application.OnKey "%c" End Sub

Table 6-3.

{Backspace} or {BS} {Break} {CapsLock} {Clear}

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Table 6-3.

{Delete} or {Del} {Down} {End} ~ (Tilde) {Enter} {F1} through {F15} {Help} {Home} {Insert} {Left} {NumLock} {PGDN} {PGUP} {Return} {Right} {ScrollLock} {Tab} {Up}

+ (Plus Sign)

^ (Caret)

% (Percent Sign)

Delete or Del Down Arrow End Enter Enter (Numeric Keypad) F1 through F15 Help Home Insert or Ins Left Arrow Num Lock Page Down Page Up Return Right Arrow Scroll Lock Tab Up Arrow Key Modifier Shift Ctrl Alt

The SendKeys method allows you to send keystrokes to the keyboard buffer for when you need to send keystrokes to the current application. This can be especially useful if you know your procedure will cause a dialog box to open and there is no method to prevent the dialog box from appearing and waiting on user input. The syntax for the SendKeys method is

expression.SendKeys (Keys, Wait)

is a required variant expression, usually expressed as a string, that contains the key codes you want to send. (See Table 6-3 for a list of key codes for special keys.)

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is an optional variant expression, usually expressed as a True or False Boolean value that specifies if the procedure should halt further execution until the keys have been processed. When True, the procedure will pause until all keys sent have been pro cessed. When False or omitted, the procedure continues execution without regard to whether or not the keys have been processed.

The keys are placed into a key buffer first until an application calls for keys from the buffer. This means the keys need to placed into the buffer before you call a method that will require the keystrokes. This example goes through a list of customers and generates a personalized e-mail message for each customer. The SendKeys method is used to pass an Alt+S keystroke to the default e-mail program to actually send the e-mail message. The Wait method is used to allow the e-mail program time to generate the e-mail message before trying to send it.

Sub SendEmail()