Child Window Controls in Windows

1. WindowsControls ChildWindowControls •Windowscreatedbyaparentwindow •Anapplicationusestheminconjunctionwithparent •NormallyusedforsimpleI/Otasks •Havealookandfeelconsistentwithotherapplication Windows •Properties,appearance,behaviordeterminedbypredefinedControlClassdefinitions –Butbehaviorcanbecustomized –EasytosetthemupascommonWindowsobjects •buttons,scrollbars,etc. •CanalsodefinecustomChildWindowControls

2. •Allowusertodisplay/selectdatainstandardways •WindowsEnvironmentdoesmostofworkin: –painting/updatingaControl'sscreenarea –determiningwhatuserisdoing •Candothe"dirtywork"forthemainwindow •Arethe"workingcomponents"ofDialogBoxes •WindowsOScontainseachcontrol's“WndProc” –somessagestocontrolsareprocessedinpredefinedways •Parent/childrelationshipwithmainwindow –Canhavehierarchiesofchildwindows –Parentandchildcommunicatebysending/receivingmessages •HavebeenpartofWindowssincethefirstversions •Rosterhasgrownfromsixbasiconestoanassortmentof 20+richandvariedcontrols Some.NETControlClasses •Button •Label(Static) •GroupBox •Panel •CheckBox •RadioButton •HScrollBar •VScrollBar •TextBox(Edit) •PictureBox •ListBox •ComboBox •StatusBar •TabControl •ToolBar

3. •ToolTip •CheckedListBox •DataGrid •DataGridTextBox •DateTimePicker •LinkLabel •ListView •MonthCalendar •NumericUpDown--spinnerbuttons •ProgressBar •PropertyGrid •RichTextBox •TrackBar •TreeView •Others CreatingaControlin.NET •Tocreateacontrolandmakeitappearonaform: 1.DeclareandInstantiateaControlclassobject ButtonmyButton; myButton=newButton(); 2.InitializetheControlobjectbysettingitsproperties myButton.Location=newPoint(10,10); myButton.Text=“ClickMe”; myButton.BackColor=Color.Red; •//etc. 3. AttachtheControltotheForm(addtoparent’scollectionofControls)…

4. AttachingControlstoaParentForm •AssumewewanttoaddmyButtonandmyLabelcontrolsto“this”Form •Threewaysofdoingit(assumewe’veinstantiatedthecontrolsmyButtonandmyLabel): 1. myButton.Parent=this; myLabel.Parent=this; 2. this.Controls.Add(myButton); this.Controls.Add(myLabel); 3. this.Controls.AddRange(newControl[]{myButton,myLabel}); •Controlsproperty:thecollectionofcontrolsattachedtotheform •#3isdoneautomaticallybytheVisualStudioDesignerwhenyou “drag”controlsontotheform SomeControlProperties/Methods •Commonpropertiesandmethods –DerivefromclassControl –Textproperty •Specifiesthetextthatappearsonacontrol –TextAlignproperty •Alignmentoftextinsidecontrol –Focus()method •Transferstheinputfocustoacontrol •Thecontrolbecomestheactivecontrol –TabIndexproperty •Determinesorderinwhichcontrolsaregiventhefocuswhenusertabs •AutomaticallysetbyVisualStudio.NETDesigner –Enabledproperty •Indicateacontrol’saccessibilityandusability

5. •Visibleproperty –Hidecontrolfromuser •OrusemethodHide() •Show()todisplayagain •AnchorandDockproperties –Anchoringcontroltospecificlocation •Constantdistancefromspecifiedlocationwhenparentisresized •DefaultinDesignerisTop-Left –Unanchoredcontrolmovesrelativetoformerposition –Dockingallowscontroltospreaditselfalonganentireside –Bothoptionsrefertotheparentcontainer •Sizeproperty •BackColor,ForeColorproperties •Image,ImageAlign,BackgroundImageproperties ControlPropertiesandLayout BeforeresizeAfterresize Constantdistance toleftandtop sides Anchoringdemonstration.

6. ControlPropertiesandLayout Darkenedbar indicatestowhich wallcontrolis anchored Clickdown-arrow inAnchorproperty todisplay anchoringwindow ManipulatingtheAnchorpropertyofacontrol. ControlLayout Controlexpandsalong topportionoftheform Dockingdemonstration.

7. ControlEvents •AllControlsderivefrom System.Windows.Forms.Control –Allinherit50+publicEvents –Somecommonones: EventEventargument ClickEventArgs DoubleClickEventArgs ControlAddedControlEventArgs ControlRemovedControlEventArgs EnterEventArgs LeaveEventArgs MoveEventArgs PaintPaintEventArgs ResizeEventArgs SizeChangedEventArgs AllothermouseeventsMouseEventArgs •EventhandlingdoneaswithFormevents AddingaButtonClickEventHandler •TheButtonClickEventDelegateisEventHandler() myButton.Click+=newEventHandler(myButton_Click); … privatevoidmyButton_Click(objectsender,System.EventArgse) { //Addhandlercodehere } •ThiscodeisinsertedautomaticallywhenyouusetheVisualStudio DesignerPropertiesWindowtoaddaClickeventhandler –OrdoubleclickontheControlinVisualStudioDesigner

8. ButtonControls •Rectangularobjects,oftenwithlabels •Intendedtotriggeranimmediateaction –Actionistriggeredbyclickingmouseonbutton –Orpressingspacebarifithastheinputfocus •SomeimportantButtonproperties: –Location,Size,BackColor,ForeColor,Cursor,Name,Text,TextAlign,Font,Image,ImageAlign,BackgroundImage,TabIndex, –Lotsofothers LabelControls •Controlsdesignedforthedisplayofstatictext –CalledStaticcontrolsinWin32 –Usercan’tchangethetext •Canbechangedincode •Canalsodisplaygraphics •HavemanyofthesamePropertiesasButtons •Canrespondtoevents,butnotreallymeanttodothat

9. Button-LabelExampleProgram •FormhasaButtoncontrolwithText:“ClickMe” •FormhasaLabelcontrolthatdisplays“HelloWorld”whenbuttonisclicked –Inresponsetothebutton’sClickevent •CanbepreparedmanuallyfromVisualStudio –Programmermustwritecodetoinstantiatethecontrols,attachthemtotheparentform,setupalltheirproperties,andaddtheButtonClickeventhandler •EasiertousetheVisualStudioDesigner –Dragabuttonandlabelcontrolfromthetoolboxtotheform •Controlsareautomaticallyinstantiated&“attached”totheform –ChangethePropertiesofeachinthePropertywindowofeach –AddtheButtonClickhandlerbydoubleclickingonthebutton •OrusingtheButton’sPropertieswindow(lightningbolt) –Addthefollowingcodeintheskeletonhandler label1.Text=“HelloWorld”; ButtonswithImages •ButtonclasshasanImageProperty –Setthatpropertytodisplayanimageonbackgroundofthebutton •CanbeusedinconjunctionwithTextProperty –Textdisplayedontopoftheimage •Makesureimagefitsinthebutton –Canuseimg.GetThumbNailImage(…)toresizetheimage •Arguments:intw,inth,Image.GetThumbnailImageAbortgt,IntPtrp •Lasttwocanspecifyacallbackfunction&data–usuallysettonulland (IntPtr)0,respectively •Returnsthethumbnailimage –Thiscanbeusedasageneralimageresizingfunction –Alternatively,makethebuttonbethesizeoftheimage •Changethebutton’sSizeproperty •ExampleProgram:Button-Image –DoessameasButton-Label,butnowbuttonhasanimageonit

10. GroupBoxandPanelControls •ArrangecomponentsonaGUI –GroupBoxescandisplayacaption •Almostalwayscontainothercontrols –RadioButtonsorCheckBoxesareverycommon –Onlyoneactiveatatime •Textpropertydeterminesitscaption –Panelsareusedtogroupothercontrolsagainstabackground •Usefulwhenyouneedacontrolthatdoesn’tdomuch •Ifcontentsofpaneltakeupmorespacethanpanelitself,attachedscrollbarscanautomaticallyappear –SousercanviewadditionalcontrolsinsidethePanel GroupBoxControlProperties GroupBoxDescription Properties Common PropertiesControlsThecontrolsthattheGroupBoxcontains.TextTextdisplayedonthetopportionofthe GroupBox(itscaption).

11. PanelControlProperties Panel Properties Description Common Properties AutoScroll WhetherscrollbarsappearwhenthePanelistoosmalltoholditscontrols.Defaultisfalse. BorderStyle BorderofthePanel(defaultNone; FixedSingle). Fixed3D otheroptionsare and Controls ThecontrolsthatthePanelcontains. Panelproperties. Panels Controls panel scrollbars CreatingaPanelwithscrollbars. panel insidepanel

12. GroupBox-PanelExample Program •OrganizesonegroupofbuttonsinaGroupBox –GroupBoxislabeled •OrganizesanothergroupofbuttonsinaPanelthatistoosmalltoviewitsbuttons –AutoScrollPropertyisset=>ScrollbarsautomaticallyappeartopermitusertoviewallthebuttonsinsidethePanel •Clickinganybuttoncausesalabelcontroltoindicatewhichbuttonwasclicked ScrollBars •UsedeverywhereinGUIs •Twopurposes: –Toshift(“scroll”)thevisibleareaofaform/control •Scrollbarisattachedtothecontrol/form •Setparentform/control’sAutoScrollPropertytotrue –Tovaryaparameter •Standalonescrollbar •ScrollbarPropertiesthatcanberead/modified: –SizeandLocationonparentcontrol/form –Range:MaximumandMinimumthumbposition –CurrentValueofthumbposition –Changevalues •SmallChange:Valuechangewhenuserclicksonendarrows •LargeChange:valuechangewhenuserclicksonareabetweenendarrowsandthumb

13. ScrollBarEvents •TwoeventsraisedbyScrollBarcontrols –ValueChanged--Data:EventArgs •RaisedwhenValuepropertyhaschanged,eitherbyaScrolleventorprogrammatically –Scroll--Data:ScrollEventArgs •Raisedwhenscrollbarthumbhasbeenmoved,eitherbymouseorkeyboard •Providesinformationabouttheevent,includingthenewvalueandtypeofevent •ScrollEventprovidesmoreinformationthanValueChanged •SomeScrollEventArgsProperties: –IntValue –ScrollEventTypeType »EnumerationMembers:SmallDecrement(LorTarrow),SmallIncrement(RorB),LargeDecrement(LorTareas),LargeInccrement(RorB),ThumbTrack(Thumbdown)ThumbPosition(thumbup),EndScroll(scrolloperationdone),Others Scroll-ImageExample •Addstandalonehorizontalandverticalscrollbarstomainform –Positionhorizontalonealongbottomofform –Verticaloneonrightside,leavingspaceonrightfor2labelcontrols •ControlthepositionofanImagewiththescrollbars •Labelcontrolsshowcurrentposition(x,y)ofimage •Events: –Paint:drawimageinitsnewposition –Scrollofhorizontalscrollbar:setnewxvalueofimageposition,changelabel1’stexttocurrentscrollbarValue,&repaint –Scrollofverticalscrollbar:setnewyvalueofimageposition,changelabel2’stexttocurrentscrollbarValue,&repaint –Resize:repositionscrollbarsandresettheirMaximumvalues

14. RadioButtons&CheckBoxes •Botharepredefined“state”buttonsthatallowusertoselectordeselectagivenoption –Canbesetto“on”or“off”(selected/unselected)state –Foreach,theCheckedPropertyissettofalseifbuttonisunselectedandtrueifselected –IfAutoCheckpropertyistrue,statetoggleswhenuserclicks •RadioButtons –Almostalwaysusedinagroupboxfromwhichonlyonebuttoninthegroupcanbeselectedatatime •Mutuallyexclusiveoptions •Theyareallchildrenofthegroupbox…whichisachildoftheform –Displayedaslittlecircles •Selectedcirclehasadotinside •CheckBoxes –Ifenclosedinagroupbox,anynumberofthemcanbeselected –Displayedaslittleboxes •Selectedboxeshavecheckmarksinthem SomeCheckBoxPropertiesand Events CheckBoxeventsandproperties Description/DelegateandEventArguments CommonProperties Checked WhetherornottheCheckBoxhasbeenchecked. CheckState WhethertheCheckboxischecked(containsablackcheckmark)orunchecked(blank).AnenumerationwithvaluesChecked,UncheckedorIndeterminate. Text TextdisplayedtotherightoftheCheckBox(calledthelabel). CommonEvents (DelegateEventHandler,eventarguments EventArgs) CheckedChanged RaisedeverytimetheCheckboxiseithercheckedorunchecked.Defaulteventwhenthiscontrolisdoubleclickedinthedesigner. CheckStateChanged RaisedwhentheCheckStatepropertychanges.

15. SomeRadioButtonProperties& Events RadioButtonDescription/DelegateandEventpropertiesandArguments eventsCommonProperties CheckedWhethertheRadioButtonischecked. TextTextdisplayedtotherightofthe CommonEvents(DelegateEventHandler,eventargumentsEventArgs) ClickRaisedwhenuserclicksthecontrol. CheckedChangedRaisedeverytimetheRadioButtonischeckedorunchecked.Defaulteventwhenthiscontrolisdoubleclickedinthedesigner. RadioButton(calledthelabel). Radio-CheckExampleProgram •Drawsopenorfilledrectanglesofdifferent colors •A‘ColorSelection’groupboxcontainingradio buttonsallowsusertoselectacolor •A‘FillRectangle’checkboxdetermineswhethertherectangleisfilledornot