我有一个名为“DTImageList”的全局数据表和一个名为“uxImageGrid”的 XtraGrid。现在有一个名为“prcFillImagesVideosAndFiles”的方法，其中我们从数据库页面明智地获取图像数据，即一次说 500 行，我们使用 XtraTabControl 在网格顶部创建手动页面，具体取决于根据存在的数据总数搜索。假设我们得到 700 张图片，那么一次只加载 500 张图片，并且 2 个页面将被创建为“第 1 页”、“第 2 页”。但是在“prcFillImagesVideosAndFiles”方法中，我们没有获取实际图像，而只是获取它的名称、ID 等。在此之后，我创建了一个新线程并调用了一个方法运行程序，该运行程序又调用了一个名为“FillImages”的新方法 在其中我查看 DTImageList 并从后端一张一张地获取实际图像并使用该图像更新行，因为 XtraGrid 开始一张一张地显示图像。这个过程可以正常工作几分钟，即加载 20-25 个图像，然后它会给出“跨线程操作无效”错误。
// 我的 prcFillImagesVideosAndFiles 方法的代码是：
`if (DTImageList != null)
{
DTImageList.Rows.Clear(); DTImageList.Columns.Clear(); DTImageList = null;
}
string sql = @"select " + top + @" IM.Image_ID,IM.extension,IM.Is_Uploaded,cast(0 as varbinary) 'ActualImage',IM.description 'Description',IM.ContentType,IM.DateTime_Uploaded,IM.FolderName, '' as FilePath
from images as IM where IM.GCRecord is null and IM.Is_Uploaded=1 " + MainCriteria + @" " + Ob + @"";
string sql1 = LayoutPaging(sql);
DTImageList = new DataTable();
DTImageList = FillDataTable(sql1);
DataTable DTdeliv2 = new DataTable();
DTdeliv2.Columns.Add("Image");
DTdeliv2.Columns.Add("UniqueNumber");
DTdeliv2.Columns["Image"].DataType = typeof(Image);
DTdeliv2.Columns["UniqueNumber"].DataType = typeof(int);
DTImageList.Merge(DTdeliv2, true, MissingSchemaAction.Add);
uxImageGrid.DataSource = null;
uxImageGrid.DataSource = DTImageList;
RepositoryItemTextEdit riTextEdit = new RepositoryItemTextEdit();
riTextEdit.Appearance.TextOptions.HAlignment = HorzAlignment.Center;
layoutView1.Columns["Description"].AppearanceCell.TextOptions.HAlignment = HorzAlignment.Center;
riTextEdit.Appearance.BackColor = System.Drawing.Color.FromArgb(((int)(((byte)(255)))), ((int)(((byte)(128)))), ((int)(((byte)(128)))));
riTextEdit.Appearance.Options.UseBackColor = true;
riTextEdit.NullText = "";
uxImageGrid.RepositoryItems.Add(riTextEdit);
layoutView1.Columns["Description"].ColumnEdit = riTextEdit;
riTextEdit.Leave += new EventHandler(riTextEdit_Leave);
riTextEdit.KeyPress += new KeyPressEventHandler(riTextEdit_KeyPress);
RepositoryItemPictureEdit riPictureEdit = new RepositoryItemPictureEdit();
riPictureEdit.SizeMode = PictureSizeMode.Zoom;
riPictureEdit.ShowMenu = false;
riPictureEdit.NullText = " Loading Image";
riPictureEdit.Appearance.Image = Pionero.RetailTherapy.Properties.Resources.mag;
uxImageGrid.RepositoryItems.Add(riPictureEdit);
layoutView1.Columns["Image"].ColumnEdit = riPictureEdit;
riPictureEdit.MouseMove += new MouseEventHandler(riPictureEdit_MouseMove);
riPictureEdit.MouseDown += new MouseEventHandler(riPictureEdit_MouseDown);
layoutView1.Columns["Image"].Caption = "";
int k = DTImageList.Rows.Count;
if (k > 0)
{
DevExpress.Data.Filtering.CriteriaOperator expr1 = new DevExpress.Data.Filtering.BinaryOperator("Is_Uploaded", true);
layoutView1.ActiveFilterCriteria = expr1;
if (pthread != null)
{
StopRunningThread();
}
if (pthread == null || pthread.IsAlive==false)
{
pthread = new Thread(new ThreadStart(runner));
pthread.IsBackground = true;
Is_ThreadNeededtoWork = true;
pthread.Start();
}
else
{
Is_ThreadNeededtoWork = true;
pthread.Start();
}
}`
//runner方法是：
void runner()
{
if (Is_ThreadNeededtoWork == false)
{
if (dtImages != null)
{
dtImages.Rows.Clear(); dtImages.Columns.Clear(); dtImages = null;
}
return;
}
if (Is_ThreadNeededtoWork == true)
{
FillImages();
}
}
// FillImages 方法的代码是：
try
{
if (DTImageList.Rows.Count <= 0) return;
StringBuilder sbImagesNotLoaded = new StringBuilder();
sbImagesNotLoaded.Append("Following images not loaded due to connection: ");
ArrayList lstImage_IDs = new ArrayList();
int NoOfAttempts = 0;
//if (dtImages != null)
//{
for (int i = 0; i < DTImageList.Rows.Count; i++)
{
NoOfAttempts = 0;
V:
string Qry = @" Select Image_ID,image from images where Image_ID = " + DTImageList.Rows[i]["Image_ID"].ToString();
dtImages = FillDataTable(Qry);
if (dtImages != null && dtImages.Rows.Count > 0)
{
if (DTImageList.Rows[i]["image"] == DBNull.Value)
{
// Thread.Sleep(100);
byte[] barr = (byte[])dtImages.Rows[0]["image"];
Image img = Global.byteArrayToImage(barr);
DTImageList.Rows[i]["Image"] = img;
DTImageList.AcceptChanges();
uxImageGrid.RefreshDataSource();
}
}
else
{
// Thread.Sleep(100);
if (Convert.ToInt32(DTImageList.Rows[i]["Image_ID"]) > 0)
if (NoOfAttempts < 3)
{
NoOfAttempts = NoOfAttempts + 1;
goto V;
}
else
{
if (lstImage_IDs.Count > 0)
sbImagesNotLoaded.Append("," + Convert.ToString(DTImageList.Rows[i]["Description"]));
else
sbImagesNotLoaded.Append(Convert.ToString(DTImageList.Rows[i]["Description"]));
lstImage_IDs.Add(DTImageList.Rows[i]["Image_ID"]);
}
}
}
//}
if (lstImage_IDs.Count > 0)
{
for (int i = 0; i < lstImage_IDs.Count; i++)
{
DataRow drImage = DTImageList.Select("Image_ID=" + Convert.ToString(lstImage_IDs[i]) + "").FirstOrDefault();
if (drImage != null)
DTImageList.Rows.Remove(drImage);
}
DTImageList.AcceptChanges();
XtraMessageBox.Show(sbImagesNotLoaded.ToString(), Global.Header, MessageBoxButtons.OK, MessageBoxIcon.Information);
}
EnableDisablePanelControls(true);
if (pthread != null)
{
Is_ThreadNeededtoWork = false;
StopRunningThread();
}
}
catch (ThreadAbortException abortException)
{
}
catch (Exception emmp)
{
EnableDisablePanelControls(true);
//pthread.Abort();
}
finally
{
//Global.StopProg();
}
//StopRunningThread() 的代码是：
void StopRunningThread()
{
if (dtImages != null)
{
dtImages.Rows.Clear(); dtImages.Columns.Clear(); dtImages = null;
}
Is_ThreadNeededtoWork = false;
}
谢谢维姬