true if the character should be sent directly to the control and not preprocessed; otherwise, false.
Call the Control.IsInputChar(char) method to determine whether the character specified by the charCode parameter is an input character that the control wants. This method is called during window message preprocessing to determine whether the specified input character should be preprocessed or sent directly to the control. If Control.IsInputChar(char) returns true, the specified character is sent directly to the control. If Control.IsInputChar(char) returns false, the specified character is preprocessed and only sent to the control if it is not consumed by the preprocessing phase. The preprocessing of a character includes checking whether the character is a mnemonic of another control.