我正在尝试根据(英国)邮政编码加载根据Google静态地图按需提取的图片。
假设我有一个客户,客户有一个地址。客户端的一个属性是PostCode。我有一个加载客户端的表单。我将客户端ID提供给此表单的构造函数,然后使用LINQ 2 SQL加载包括地址在内的各种信息。
private void LoadBranchDetails() {
Text_Update_BI_Name.Text = Branch.BranchNumber;
Text_Update_BI_Manager.Text = String.Format("{0} {1}", Branch.PharmacyManager.FirstName, Branch.PharmacyManager.LastName);
DropDownList_Update_BI_Coordinator.SelectedValue = Branch.CoordinatorID;
DropDownList_Update_BI_ComputerSystem.SelectedValue = Branch.ComputerSystemID;
Text_Update_BI_Phone.Text = Branch.PhoneNumber;
Text_Update_BI_Fax.Text = Branch.FaxNumber;
Address BranchAddress = Branch.Contact.Addresses.FirstOrDefault();
Text_Update_AI_House.Text = BranchAddress.HouseNumber;
Text_Update_AI_Street.Text = BranchAddress.Street;
Text_Update_AI_Area.Text = BranchAddress.Area;
Text_Update_AI_Post.Text = BranchAddress.PostCode;
DropDownList_Update_AI_City.SelectedValue = BranchAddress.City.OID;
MaskedText_Update_OI_NoPharmacist.Value = Branch.NumberOfPharmacists;
MaskedText_Update_OI_NoDispensers.Value = Branch.NumberOfDispensers;
MaskedText_Update_OI_NoMonFri.Value = Branch.NumberOfItemsMondayToFriday;
MaskedText_Update_OI_NoSat.Value = Branch.NumberOfItemsSaturday;
MaskedText_Update_OI_NoSun.Value = Branch.NumberOfItemsSunday;
MaskedText_Update_OI_NoAddicts.Value = Branch.NumberOfAddicts;
MaskedText_Update_OI_NoSupervised.Value = Branch.Supervised;
MaskedText_Update_OI_NoUnsupervised.Value = Branch.Unsupervised;
Check_Update_OI_ConfRoom.Checked = Branch.ConsultationRoom;
try {
PictureGoogleMaps.Image = GoogleAddressInfo.FetchMapInfo(Text_Update_AI_Post.Text).GoogleStaticMap;
} catch (Exception) {
PictureGoogleMaps.Image = Resources.DefaultGoogleMap;
}
}
将图片加载到PictureGoogleMaps中的行会导致UI挂起,因为“。googleStaticMap”属性会在调用时生成Google静态图片。
在网上搜索时,我发现了这个有用的例子:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
// Declare a list of URLs and their respective picture boxes
var items = new Dictionary<string, PictureBox>
{
{ "http://www.google.com/logos/spring09.gif", new PictureBox() { Top = 0, Width = 300, Height = 80 } },
{ "http://www.google.com/logos/stpatricks_d4gwinner_eo09.gif", new PictureBox() { Top = 100, Width = 300, Height = 80 } },
{ "http://www.google.com/logos/schiaparelli09.gif", new PictureBox() { Top = 200, Width = 300, Height = 80 } },
{ "http://www.google.com/logos/drseuss09.gif", new PictureBox() { Top = 300, Width = 300, Height = 80 } },
{ "http://www.google.com/logos/valentines09.gif", new PictureBox() { Top = 400, Width = 300, Height = 80 } },
{ "http://www.google.com/logos/unix1234567890.gif", new PictureBox() { Top = 500, Width = 300, Height = 80 } },
{ "http://www.google.com/logos/charlesdarwin_09.gif", new PictureBox() { Top = 600, Width = 300, Height = 80 } },
};
foreach (var item in items)
{
var worker = new BackgroundWorker();
worker.DoWork += (o, e) =>
{
// This function will be run on a background thread
// spawned from the thread pool.
using (var client = new WebClient())
{
var pair = (KeyValuePair<string, PictureBox>)e.Argument;
e.Result = new KeyValuePair<PictureBox, byte[]>(pair.Value, client.DownloadData(pair.Key));
}
};
worker.RunWorkerCompleted += (o, e) =>
{
// This function will be run on the main GUI thread
var pair = (KeyValuePair<PictureBox, byte[]>)e.Result;
using (var stream = new MemoryStream(pair.Value))
{
pair.Key.Image = new Bitmap(stream);
}
Controls.Add(pair.Key);
};
worker.RunWorkerAsync(item);
}
}
}
现在我只需要弄清楚如何删除for循环并在我的场景中使用它。有什么想法吗?
示例代码来自此link。
感谢。
答案 0 :(得分:1)
去除foreach循环难吗?您只需要加载一张图片,然后删除foreach循环并将图片的网址和目标图片框传递给后台工作者。
答案 1 :(得分:1)
public partial class Form1 : Form
{
private BackgroundWorker imageLoader;
public Form1()
{
InitializeComponent();
this.imageLoader = new BackgroundWorker();
this.imageLoader.DoWork += HandleOnImageLoaderDoWork;
this.imageLoader.RunWorkerCompleted += HandleImageLoaderOnRunWorkerCompleted;
this.LoadUserDetails(1);
}
private void LoadUserDetails(Int32 userID)
{
this.imageLoader.RunWorkerAsync(userID.ToString());
// get the user details
// populate the UI controls with the data....
}
private void HandleImageLoaderOnRunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e)
{
this.pictureBox1.Image = (Image)e.Result;
}
private void HandleOnImageLoaderDoWork(Object sender, DoWorkEventArgs e)
{
// simulate a web request for an image;
Thread.Sleep(3000);
Image image = Image.FromFile(@"test.jpg");
e.Result = image;
}
}
还要确保显示一些后台操作正在进行的UI通知...类似于PictureBox中的初始图像(loading.gif)。