覆蓋表單
覆蓋表單是執(zhí)行以下操作的半透明啟動(dòng)屏幕:
- 覆蓋控件或表單
- 防止用戶與重疊控件進(jìn)行交互
- 覆蓋控件,即使它更改其大小或在屏幕上的位置
- 在單獨(dú)的線程中運(yùn)行,并且不阻塞主線程和操作線程
- 允許您在重疊控件上顯示自定義消息和按鈕
注意:運(yùn)行Overlay Form module in the XtraEditors MainDemo來(lái)查看正在使用的表單,單擊功能區(qū)中的Open Solution獲取源代碼。
顯示覆蓋表單
調(diào)用ShowOverlayForm(Control) 方法來(lái)在控件或表單上顯示覆蓋表單,該方法返回一個(gè)句柄,您可以將其傳遞給 CloseOverlayForm(IOverlaySplashScreenHandle)方法來(lái)關(guān)閉表單。
下面的代碼顯示在應(yīng)用程序執(zhí)行長(zhǎng)時(shí)間運(yùn)行的操作時(shí)如何在當(dāng)前表單上顯示覆蓋表單。
C#:
using DevExpress.XtraSplashScreen; //... IOverlaySplashScreenHandle ShowProgressPanel() { return SplashScreenManager.ShowOverlayForm(this); } void CloseProgressPanel(IOverlaySplashScreenHandle handle) { if(handle != null) SplashScreenManager.CloseOverlayForm(handle); } //... IOverlaySplashScreenHandle handle = null; try { handle = ShowProgressPanel(); // Launch a long-running operation while // the Overlay Form overlaps the current form. } finally { CloseProgressPanel(handle); }
VB.NET :
Imports DevExpress.XtraSplashScreen '... Private Function ShowProgressPanel() As IOverlaySplashScreenHandle Dim handle As IOverlaySplashScreenHandle = SplashScreenManager.ShowOverlayForm(Me) Return handle End Function Private Sub CloseProgressPanel(ByVal handle As IOverlaySplashScreenHandle) If handle IsNot Nothing Then SplashScreenManager.CloseOverlayForm(handle) End Sub '... Dim Handle As IOverlaySplashScreenHandle = Nothing Try Handle = ShowProgressPanel() 'Launch a long-running operation while 'the Overlay Form overlaps the main form. Finally CloseProgressPanel(Handle) End Try
警告:您只能在已初始化(創(chuàng)建其句柄)的控件/表單上顯示覆蓋表單,否則將拋出InvalidOperationException,請(qǐng)參見(jiàn) IsHandleCreated 。
疊加表單手柄
您也可以使用句柄的Close()方法來(lái)關(guān)閉疊加表單。
顯示疊加表單時(shí),聚焦控件將失去焦點(diǎn),當(dāng)Overlay Form關(guān)閉時(shí),此控件將重新獲得焦點(diǎn)。QueueFocus(Control)和QueueFocus(IntPtr)方法允許您指定在關(guān)閉Overlay Form時(shí)應(yīng)該聚焦的控件,傳遞 IntPtr.Zero來(lái)防止所有控件都有焦點(diǎn)。
您也可以使用QueueCloseUpAction(Action)方法來(lái)指定當(dāng)Overlay Form關(guān)閉時(shí)應(yīng)該執(zhí)行的動(dòng)作。
C#:
void ReloadData() { using(var handle = SplashScreenManager.ShowOverlayForm(gridControl)) { handle.QueueFocus(IntPtr.Zero); ReloadDataCore(); } }
VB.NET :
Private Sub ReloadData() Using handle = SplashScreenManager.ShowOverlayForm(gridControl) handle.QueueFocus(IntPtr.Zero) ReloadDataCore() End Using End Sub
自定義覆蓋表單
ShowOverlayForm(Control, OverlayWindowOptions方法允許您顯示具有以下參數(shù)的覆蓋表單:
- StartupDelay ——顯示表單之前的延遲。
- BackColor —— 背景顏色。
- Opacity —— 不透明表單。
- FadeIn, FadeOut —— 用于顯示和隱藏表單的淡入淡出效果。
-
AnimationType —— 動(dòng)畫的類型(等待指示符):
-
Image ——旋轉(zhuǎn)的圖像,默認(rèn)圖像取決于皮膚。 使用ImageSize屬性指定默認(rèn)圖像的大小,默認(rèn)圖像大小取決于重疊控件的大小,Image屬性指定一個(gè)自定義圖像。
RotationParameters屬性指定旋轉(zhuǎn)周期和單旋轉(zhuǎn)幀數(shù)。 - Line —— 使用LineAnimationParameters屬性指定點(diǎn)數(shù),點(diǎn)的大小以及點(diǎn)之間的距離。
-
Image ——旋轉(zhuǎn)的圖像,默認(rèn)圖像取決于皮膚。 使用ImageSize屬性指定默認(rèn)圖像的大小,默認(rèn)圖像大小取決于重疊控件的大小,Image屬性指定一個(gè)自定義圖像。
- DisableInput——重疊表單是否接收焦點(diǎn)并禁用重疊控件上的用戶輸入,關(guān)閉疊加表單后,它將焦點(diǎn)返回到控件。
- CustomPainter —— 一個(gè)用于繪制表單的OverlayWindowPainterBase后代。
- SkinName —— 應(yīng)用于表單的skin名稱,默認(rèn)的等待指示器,淡入淡出效果和顏色取決于皮膚,默認(rèn)外觀對(duì)應(yīng)于重疊控件的外觀
- UseDirectX —— 指定是否使用DirectX渲染覆蓋表單,要將DirectX用于所有兼容的DevExpress控件,請(qǐng)?jiān)?a href="http://www.xiangyinys.com/doclib/s/2/15740">Project Settings中啟用Use DirectX選項(xiàng)。
所有這些參數(shù)都是可選的,如果省略參數(shù),則使用默認(rèn)值,不帶選項(xiàng)的ShowOverlayForm(Control)方法使用靜態(tài)(在VB中共享)默認(rèn)選項(xiàng)。
下面的代碼顯示了如何顯示帶有自定義參數(shù)的覆蓋表單。
C#:
using DevExpress.XtraSplashScreen; OverlayWindowOptions options = new OverlayWindowOptions( startupDelay: 1000, backColor: Color.Red, opacity: 0.5, fadeIn: false, fadeOut: false, imageSize: new Size(64, 64) ); IOverlaySplashScreenHandle handle1 = SplashScreenManager.ShowOverlayForm(gridControl1, options); IOverlaySplashScreenHandle handle2 = SplashScreenManager.ShowOverlayForm( owner: gridControl1, startupDelay: 1000, backColor: Color.Red, opacity: 127, fadeIn: false, fadeOut: false, imageSize: new Size(64, 64) );
VB.NET :
Imports DevExpress.XtraSplashScreen Dim options As New OverlayWindowOptions( startupDelay:=1000, backColor:=Color.Red, opacity:=0.5, fadeIn:=False, fadeOut:=False, imageSize:=New Size(64, 64) ) Dim formHandle1 As IOverlaySplashScreenHandle = SplashScreenManager.ShowOverlayForm(gridControl1, options) Dim formHandle2 As IOverlaySplashScreenHandle = SplashScreenManager.ShowOverlayForm( owner:=gridControl1, startupDelay:=1000, backColor:=Color.Red, opacity:=127, fadeIn:=False, fadeOut:=False, imageSize:=New Size(64, 64) )
自定義Painter
您可以按以下方式呈現(xiàn)重疊表單:
- 繼承自O(shè)verlayWindowPainterBase類
- 重寫Draw方法
- 將創(chuàng)建的對(duì)象作為參數(shù)傳遞給ShowOverlayForm方法
下面的代碼段顯示了如何顯示自定義消息,如下圖所示:
C#:
using DevExpress.XtraSplashScreen; using DevExpress.Utils.Drawing; using System.Drawing; //... class CustomOverlayPainter : OverlayWindowPainterBase { // Defines the string’s font. static readonly Font drawFont; static CustomOverlayPainter() { drawFont = new Font("Tahoma", 18); } protected override void Draw(OverlayWindowCustomDrawContext context) { //The Handled event parameter should be set to true. //to disable the default drawing algorithm. context.Handled = true; //Provides access to the drawing surface. GraphicsCache cache = context.DrawArgs.Cache; //Adjust the TextRenderingHint option //to improve the image quality. cache.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias; //Overlapped control bounds. Rectangle bounds = context.DrawArgs.Bounds; //Draws the default background. context.DrawBackground(); //Specify the string that will be drawn on the Overlay Form instead of the wait indicator. String drawString = "Please wait..."; //Get the system's black brush. Brush drawBrush = Brushes.Black; //Calculate the size of the message string. SizeF textSize = cache.CalcTextSize(drawString, drawFont); //A point that specifies the upper-left corner of the rectangle where the string will be drawn. PointF drawPoint = new PointF( bounds.Left + bounds.Width / 2 - textSize.Width / 2, bounds.Top + bounds.Height / 2 - textSize.Height / 2 ); //Draw the string on the screen. cache.DrawString(drawString, drawFont, drawBrush, drawPoint); } } //... IOverlaySplashScreenHandle handle = SplashScreenManager.ShowOverlayForm(this, customPainter: new CustomOverlayPainter());
VB.NET :
Imports DevExpress.Utils.Drawing Imports DevExpress.XtraSplashScreen Imports System.Drawing '... Class CustomOverlayPainter Inherits OverlayWindowPainterBase 'Defines the string’s font. Shared ReadOnly drawFont As Font Shared Sub New() drawFont = New Font("Tahoma", 18) End Sub Protected Overrides Sub Draw(context As OverlayWindowCustomDrawContext) 'The Handled event parameter should be set to true 'to disable the default drawing algorithm. context.Handled = True 'Provides access to the drawing surface. Dim cache As GraphicsCache = context.DrawArgs.Cache 'Adjust the TextRenderingHint option ’to improve the image quality. cache.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias 'Overlapped control bounds. Dim bounds As Rectangle = context.DrawArgs.Bounds 'Draws the default background. context.DrawBackground() 'Create the string to draw. Dim drawString As String = "Please wait..." 'Get the system black brush. Dim drawBrush As Brush = Brushes.Black 'Calculate the size of the message string. Dim textSize As SizeF = cache.CalcTextSize(drawString, drawFont) 'A point that specifies the upper-left corner of the rectangle where the string should be drawn. Dim drawPoint As PointF = New PointF(bounds.Left + bounds.Width / 2 - textSize.Width / 2, bounds.Top + bounds.Height / 2 - textSize.Height / 2) 'Draw the string on the screen. cache.DrawString(drawString, drawFont, drawBrush, drawPoint) End Sub End Class '... Dim handle As IOverlaySplashScreenHandle = SplashScreenManager.ShowOverlayForm(Me, customPainter:=New CustomOverlayPainter())