winform Loading效果

做winform项目时，有可能用到异步耗时加载数据啥的，这个时候就需要我们封装一个正在加载的效果。下面是实现思路：

步骤一：把当前form界面使用句柄的方式截图出一个图片，这个图片会在下面用到，使用句柄获取截图的方式会在最后代码展示里附录上。

步骤二：定义一个和当前form一样大小的panel,让这个panel带到当前form的Z顺序的最前面，把当前界面覆盖住，这样当前form的控件就不可点击。

步骤三：把从步骤一获取的图片设置为步骤而定义的panel的背景，这样让这个panel看起来是和界面一样的。

步骤四：在panel中间定义一个新的panel放置加载Loading图片和文字。

下面是封装的代码：

  1 public partial class customForm : Form
  2     {
  3         #region properties
  4 
  5         /// <summary>
  6         /// 显示的等待框
  7         /// </summary>
  8         private System.Windows.Forms.Panel waitingBox;
  9 
 10         Panel waitingBoxInnerPanel;
 11 
 12         Label waitingBoxLab;
 13 
 14         private PictureBox _waitPicBox;
 15 
 16         private bool _IsWaitingBoxCreated = false;
 17 
 18         private bool _isOnWaiting = false;
 19 
 20         #endregion
 21 
 22         public baseLogin()
 23         {
 24             InitializeComponent();
 25 
 26             //设置程序图标
 27             Icon = Icon.FromHandle(Properties.Resources.icon.GetHicon());
 28 
 29             //Task.Delay(1000).ContinueWith((t) => { CreateWaitingBox(); });
 30         }
 31 
 32         public void ShowProgress(string message = "", int second = 60)
 33         {
 34             if (_isOnWaiting)
 35             {
 36                 return;
 37             }
 38             _isOnWaiting = true;
 39             this.Invoke(new Action(() =>
 40             {
 41                 CreateWaitingBox();
 42                 SetWaitingMessage(message);
 43                 waitingBox.Visible = true;
 44                 waitingBox.BringToFront();
 45             }));
 46         }
 47 
 48         public void ShowMessage(string message = "", int second = 2)
 49         {
 50             if (_isOnWaiting)
 51             {
 52                 return;
 53             }
 54             _isOnWaiting = true;
 55             CreateWaitingBox();
 56             SetWaitingMessage(message);
 57             if (IsHandleCreated)
 58             {
 59                 this.Invoke(new Action(() =>
 60                 {
 61                     waitingBox.Visible = true;
 62                     waitingBox.BringToFront();
 63                 }));
 64                 Task.Delay(second * 1000).ContinueWith((t) =>
 65                 {
 66                     DisMissMessage();
 67                 });
 68             }
 69         }
 70 
 71         public void DisMissMessage()
 72         {
 73             if (waitingBox == null)
 74             {
 75                 return;
 76             }
 77             if (!waitingBox.Visible)
 78             {
 79                 return;
 80             }
 81             else
 82             {
 83                 this.Invoke(new Action(() =>
 84                 {
 85                     waitingBox.Visible = false;
 86                     this._isOnWaiting = false;
 87                 }));
 88             }
 89         }
 90 
 91         #region private
 92 
 93         private void CreateWaitingBox()
 94         {
 95 
 96             if (this.IsHandleCreated)
 97             {
 98                 this.Invoke(new Action(() =>
 99                {
100                    //Image backImg = this.CreateBacgroundImage();
101                    Control frm = this;
102                    Image backImg = CaptureImage(ref frm);
103                    if (!_IsWaitingBoxCreated)
104                    {
105                        waitingBox = new Panel()
106                        {
107                            Visible = false,
108                        };
109                        waitingBox.BackColor = Color.FromArgb(234, 244, 252);
110 
111                        waitingBoxInnerPanel = new Panel();
112                        waitingBoxInnerPanel.Width = 280;
113                        waitingBoxInnerPanel.Height = 80;
114                        waitingBoxInnerPanel.BackColor = Color.Gray;
115                        waitingBoxInnerPanel.Padding = new Padding(8, 5, 5, 5);
116 
117                        waitingBoxLab = new Label();
118                        waitingBoxLab.TextAlign = ContentAlignment.MiddleLeft;
119                        waitingBoxLab.AutoEllipsis = true;
120                        waitingBoxLab.Dock = DockStyle.Fill;
121 
122                        waitingBoxInnerPanel.Controls.Add(waitingBoxLab);
123 
124                        PictureBox pb = new PictureBox();
125                        pb.Dock = DockStyle.Left;
126                        pb.Size = new System.Drawing.Size(72, 70);
127                        pb.Image = Properties.Resources.loading;
128                        pb.Margin = new System.Windows.Forms.Padding(3, 3, 20, 3);
129                        pb.SizeMode = PictureBoxSizeMode.StretchImage;
130                        this._waitPicBox = pb;
131                        waitingBoxInnerPanel.Controls.Add(pb);
132 
133                        waitingBox.Controls.Add(waitingBoxInnerPanel);
134                        //waitingBox.BringToFront();
135                        if (!this.Controls.Contains(waitingBox))
136                        {
137                            this.Controls.Add(waitingBox);
138                        }
139                        //waitingBox.Show();
140 
141                        this._IsWaitingBoxCreated = true;
142 
143                    }
144 
145                    Rectangle rect = this.ClientRectangle;
146                    waitingBox.Width = rect.Width;
147                    waitingBox.Height = rect.Height;
148                    waitingBox.Location = new Point(rect.X, rect.Y);
149 
150                    waitingBox.BackgroundImage = backImg;
151                    waitingBox.BackgroundImageLayout = ImageLayout.Stretch;
152                }));
153             }
154         }
155 
156         /// <summary>
157         /// 设置等待显示的信息
158         /// </summary>
159         /// <param name="message">The message.</param>
160         /// User:Ryan  CreateTime:2012-8-5 16:22.
161         private void SetWaitingMessage(string message)
162         {
163             if (this.IsHandleCreated)
164             {
165                 this.Invoke(new Action(() =>
166                 {
167                     message = " " + message.Trim();
168                     if (this.waitingBoxLab != null && this.waitingBoxInnerPanel != null)
169                     {
170                         using (Graphics g = this.CreateGraphics())
171                         {
172                             int w = Convert.ToInt32(g.MeasureString(message, this.waitingBoxLab.Font).Width);
173                             w = w >= 200 ? w : 200;
174                             w = this.Width - 100 >= w ? w : this.Width - 100;
175                             this.waitingBoxInnerPanel.Width = w + 60;
176                             waitingBoxInnerPanel.Location = new Point(waitingBox.Bounds.X + waitingBox.Width / 2 - waitingBoxInnerPanel.Width / 2,
177                                 waitingBox.Bounds.Y + waitingBox.Height / 2 - waitingBoxInnerPanel.Height);
178                         }
179 
180                         this.waitingBoxLab.Text = message;
181                     }
182                 }));
183             }
184         }
185 
186         private Bitmap CreateBacgroundImage()
187         {
188             Rectangle rect = this.ClientRectangle;
189             int w = rect.Width;
190             int h = rect.Height;
191             try
192             {
193                 Bitmap img = new Bitmap(w, h);
194                 using (Graphics g = Graphics.FromImage(img))
195                 {
196                     g.CopyFromScreen(new Point(this.Location.X, this.Location.Y), new Point(0, 0), new Size(w, h));
197                 }
198                 //img.Save("a.jpg");
199                 return img;
200             }
201             catch (Exception ex)
202             {
203                 return null;
204             }
205         }
206 
207 
208         public Bitmap CaptureImage(ref Control c)
209         {
210             int hDC;
211             int sh;
212             int sw;
213             if (c == null)
214             {
215                 hDC = GetDC(0);
216                 sw = Screen.PrimaryScreen.Bounds.Width;
217                 sh = Screen.PrimaryScreen.Bounds.Height;
218             }
219             else
220             {
221                 hDC = GetDC((int)c.Handle);
222                 sw = c.Width;
223                 sh = c.Height;
224             }
225             int hMDC = CreateCompatibleDC(hDC);
226             int hBMP = CreateCompatibleBitmap(hDC, sw, sh);
227             int hBMPOld = SelectObject(hMDC, hBMP);
228             BitBlt(hMDC, 0, 0, sw, sh, hDC, 0, 0, 0xcc0020);
229             hBMP = SelectObject(hMDC, hBMPOld);
230             Bitmap result = Image.FromHbitmap(new IntPtr(hBMP));
231             DeleteDC(hDC);
232             DeleteDC(hMDC);
233             DeleteObject(hBMP);
234             return result;
235         }
236         [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleBitmap")]
237         public static extern int CreateCompatibleBitmap(int hdc, int nWidth, int nHeight);
238         [DllImport("gdi32.dll", EntryPoint = "CreateCompatibleDC")]
239         public static extern int CreateCompatibleDC(int hdc);
240         [DllImport("user32.dll", EntryPoint = "GetDC")]
241         public static extern int GetDC(int hwnd);
242         [DllImport("gdi32.dll", EntryPoint = "DeleteDC")]
243         public static extern int DeleteDC(int hdc);
244         [DllImport("gdi32.dll", EntryPoint = "SelectObject")]
245         public static extern int SelectObject(int hdc, int hObject);
246         [DllImport("gdi32.dll", EntryPoint = "DeleteObject")]
247         public static extern int DeleteObject(int hObject);
248         [DllImport("gdi32.dll", EntryPoint = "BitBlt")]
249         public static extern int BitBlt(int hDestDC, int x, int y, int nWidth, int nHeight, int hSrcDC, int xSrc, int ySrc, int dwRop);
250 
251 
252         #endregion
253 
254     }

封装代码

下面是示例代码：

1  public partial class Form1:customForm
2 {
3      private void button1_Click(object sender,EventArgs e)
4      {
5             ShowMessage("我是消息");
6       }
7 }