c# - 为什么在某个特定场景中，Bing map 上仅显示我的一部分 Pin 图？

Question

在我的应用程序中，用户可以加载一个文本文件(以分号分隔)，该文件描述了要在 Bing map 上转换为 [Push] Pins 的位置特征，或者加载预先存在的 map 数据(来自本地数据库)到同样的目的。
在从数据库加载的情况下，它工作得很好， map 上会为数据库中的每个相应记录显示一个 Pin，例如:

但是，当我从文本文件的内容中填充数据库，然后根据这些值创建 Pin 图时， map 上只会显示 pin 的一个子集——实际上通常只是前两个!
但是，当我从数据库加载相同的 map 时，所有内容都按原样显示。
从文本文件生成新记录后，我检查了数据库，所有记录确实都在那里(包括坐标(纬度和经度值)。两种情况下的代码似乎相同。但它没有显示所有针...
文本文件内容是这样的(这就是创建上面显示的 map 的原因):

Paris, France;;Paris;France;75000
Florence, Italy;;Florence;Italy;50100
Chelsea, London, England;23 Tedworth Square;Chelsea London;England;SW3 4DY
Kaltenleutgeben, Austria;;Kaltenleutgeben;Austria;2380
Vienna, Austria;;Vienna;Austria;1010
Weggis, Switzerland;;Weggis;Switzerland;6006
Heidelberg, Germany;;Heidelberg;Germany;69115
Munich, Germany;;Munich;Germany;80331

为了深入了解细节，以下是从文本文件加载 map 数据的主窗体中的代码，例如上面显示的那个:

private void toolStripMenuItemCreateMapAndLocsFromFile_Click(object sender, EventArgs e)
{
    bool pushpinsAdded = false;
    string _currentMap = string.Empty;
    RemoveCurrentPushpins();

    using (var frmCre8MapAndLocsFromFile = new mdlDlgCreateMapAndLocsFromTSVFile())
    {
        if (frmCre8MapAndLocsFromFile.ShowDialog() == DialogResult.OK)
        {
            _currentMap = mdlDlgCreateMapAndLocsFromTSVFile.CurrentMap;
            foreach (Pushpin pin in frmCre8MapAndLocsFromFile.Pins)
            {
                this.userControl11.myMap.Children.Add(pin);
                pushpinsAdded = true; // redundant after the first assignment
            }
        }
    }
    if (pushpinsAdded)
    {
        RightsizeZoomLevelForAllPushpins();
    }
    lblMapName.Text = currentMap;
    lblMapName.Visible = true;
}

这是来自 mdlDlgCreateMapAndLocsFromTSVFile 的相关代码(是的，它的名字有误，因为我从 TSV 切换到了 SCSV)，它在上面被调用:

private void btnOpenTSVFile_Click(object sender, EventArgs e)
{
    string pathToFile = string.Empty;
    string line = string.Empty;
    int counter = 0;
    openTSVFileDlg.Filter = "scsv files (*.scsv)|*.scsv|txt files (*.txt)|*.txt|All files (*.*)|*.*";
    
    if (openTSVFileDlg.ShowDialog() == DialogResult.OK)
    {
        pathToFile = openTSVFileDlg.FileName;
        fileNameOnly = Path.GetFileName(pathToFile); 
        fileNameOnly = Path.ChangeExtension(fileNameOnly, null);
        CurrentMap = fileNameOnly;
        if (SCSVFileAlreadyLoaded(fileNameOnly))
        {
            MessageBox.Show(String.Format("The file/table {0} has already been loaded/populated", fileNameOnly));
            return;
        }
        StreamReader file = new StreamReader(pathToFile);
        while ((line = file.ReadLine()) != null)
        {
            if (counter == 0)
            {
                InsertMapRecord(fileNameOnly);
            }
            counter++;
            InsertMapDetailRecord(fileNameOnly, line);
        }
    }
}

InsertMapDetailRecord() 是将图钉添加到列表中的方法，它是:

private void InsertMapDetailRecord(string fileNameOnly, string line)
{
    string keyRecordElements = string.Empty;
    string[] lineElements;
    lineElements = line.Split(';');
    string locationName = lineElements[0].Trim();
    string address = lineElements[1].Trim();
    string city = lineElements[2].Trim();
    string st8 = lineElements[3].Trim();
    string zip = lineElements[4].Trim();
    keyRecordElements = string.Format("{0} {1} {2} {3}", address, city, st8, zip).Trim();
    if (MissingValues(lineElements))
    {
        MessageBox.Show("Could not insert record - one or more key values missing");
        return;
    }

    if (InsertIntoCartographerDetail(fileNameOnly, locationName, address, city, st8, zip))
    {
        AddPushpin(keyRecordElements, locationName);
    }
    else
    {
        MessageBox.Show("insert failed");
    }
}

AddPushpin() 是:

private async void AddPushpin(string _fullAddress, string _location)
{
    iContentCounter = iContentCounter + 1;
    // from https://stackoverflow.com/questions/65752688/how-can-i-retrieve-latitude-and-longitude-of-a-postal-address-using-bing-maps
    var request = new GeocodeRequest();
    request.BingMapsKey = "Gr8GooglyMoogly";
    request.Query = _fullAddress;

    var result = await request.Execute();
    if (result.StatusCode == 200)
    {
        var toolkitLocation = (result?.ResourceSets?.FirstOrDefault())
                ?.Resources?.FirstOrDefault()
                as BingMapsRESTToolkit.Location;
        var latitude = toolkitLocation.Point.Coordinates[0];
        var longitude = toolkitLocation.Point.Coordinates[1];
        var mapLocation = new Microsoft.Maps.MapControl.WPF.Location(latitude, longitude);
        this.Pin = new Pushpin() { Location = mapLocation, ToolTip = _location, Content = iContentCounter 
     };
        if (null == this.Pins)
        {
            this.Pins = new List<Pushpin>();
        }
        this.Pins.Add(Pin); // specific to this form
        UpdateDetailRecWithCoords(_location, latitude, longitude); 
        this.DialogResult = DialogResult.OK;
    }
}

同样，就填充数据库而言，这完成了它应该做的事情，包括详细信息表的纬度和经度字段，但是在模式对话框关闭时焦点传递回主窗体后， map 上只显示两个图钉。
以下是调用 mdlDlgFrm_LoadExistingMap 的主窗体中的代码:

private void loadExistingMapToolStripMenuItem_Click(object sender, EventArgs e)
{
    bool pushpinsAdded = false;
    RemoveCurrentPushpins();
    using (var frmLoadExistingMap = new mdlDlgFrm_LoadExistingMap())
    {
        if (frmLoadExistingMap.ShowDialog() == DialogResult.OK)
        {
            foreach (Pushpin pin in frmLoadExistingMap.Pins) 
            {
                this.userControl11.myMap.Children.Add(pin);
                pushpinsAdded = true;
            }
        }
    }
    if (pushpinsAdded)
    {
        RightsizeZoomLevelForAllPushpins();
    }
    lblMapName.Text = currentMap;
    lblMapName.Visible = true;
}

这是来自 mdlDlgFrm_LoadExistingMap 表单的代码，其中:

private void btnLoadSelectedMap_Click(object sender, EventArgs e)
{
    string latitudeAsStr = string.Empty;
    string longitudeAsStr = string.Empty;
    List<MapDetails> lstMapDetails = new List<MapDetails>();
    MapDetails md;
    const int LOC_NAME = 0;
    const int ADDRESS = 1;
    const int CITY = 2;
    const int ST8 = 3;
    const int ZIP = 4;
    const int NOTES = 5;
    const int LATITUDE = 6;
    const int LONGITUDE = 7;
 
    mapName = cmbxMaps.Text.Trim();
    if (mapName == string.Empty)
    {
        MessageBox.Show("Select a map from the combo box");
        cmbxMaps.Focus();
        return;
    }
    try
    {
        Form1.currentMap = mapName; 
        string qry = "SELECT LocationName, Address1, City, StateOrSo, PostalCode, " +
                                "MapDetailNotes, Latitude, Longitude " +
                                "FROM CartographerDetail " +
                                "WHERE FKMapName = @FKMapName";
        var con = new SqliteConnection(connStr);
        con.Open();
        SqliteCommand cmd = new SqliteCommand(qry, con);
        cmd.Parameters.AddWithValue("@FKMapName", mapName);
        var reader = cmd.ExecuteReader();
        while (reader.Read())
        {
            md = new MapDetails();
            md.LocationName = reader.GetValue(LOC_NAME).ToString().Trim();
            md.Address = reader.GetValue(ADDRESS).ToString().Trim();
            md.City = reader.GetValue(CITY).ToString().Trim();
            md.StateOrSo = reader.GetValue(ST8).ToString().Trim();
            md.PostalCode = reader.GetValue(ZIP).ToString().Trim();
            md.MapDetailNotes = reader.GetValue(NOTES).ToString();
            latitudeAsStr = reader.GetValue(LATITUDE).ToString();
            if (string.IsNullOrEmpty(latitudeAsStr))
            {
                md.Latitude = 0.0;
            }
            else
            {
                md.Latitude = Convert.ToDouble(reader.GetValue(LATITUDE).ToString());
            }
            longitudeAsStr = reader.GetValue(LONGITUDE).ToString();
            if (string.IsNullOrEmpty(longitudeAsStr))
            {
                md.Longitude = 0.0;
            }
            else
            {
                md.Longitude = Convert.ToDouble(reader.GetValue(LONGITUDE).ToString());
            }
            lstMapDetails.Add(md);
        }
        AddPushpinsToListOfPushpins(lstMapDetails);
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
    this.Close();
}

// AddPushpins (plural)
private void AddPushpinsToListOfPushpins(List<MapDetails> lstMapDetails)
{
    string fullAddress;

    foreach (MapDetails _md in lstMapDetails)
    {
        fullAddress = string.Format("{0} {1} {2} {3}", _md.Address, _md.City, _md.StateOrSo, _md.PostalCode).Trim();
        AddPushpinToListOfPushpins(_md.LocationName, fullAddress, _md.MapDetailNotes, _md.Latitude,                 _md.Longitude);
    }
}

// AddPushpin (singular)
private async void AddPushpinToListOfPushpins(string location, string fullAddress, string mapDetailNotes, double latitude, double longitude)
{
    iContentCounter = iContentCounter + 1;
    string toolTip = string.Empty;
    // if already have the record, including the coordinates, no need to make the REST call
    if ((latitude != 0.0) && (longitude != 0.0))
    {
        if (mapDetailNotesExist(location))
        {
            toolTip = String.Format("{0}{1}{2}{1}{3},{4}{1}{5}", location, Environment.NewLine, fullAddress, latitude,                 longitude, mapDetailNotes.Trim());
        }
        else
        {
            toolTip = String.Format("{0}{1}{2}{1}{3},{4}", location, Environment.NewLine, fullAddress, latitude,                         longitude);
        }
        var _mapLocation = new Microsoft.Maps.MapControl.WPF.Location(latitude, longitude);
        this.Pins.Add(new Pushpin()
        {
            Location = _mapLocation,
            ToolTip = toolTip,
            Content = iContentCounter
        });
    }
    else
    {
        // from https://stackoverflow.com/questions/65752688/how-can-i-retrieve-latitude-and-longitude-of-a-postal-                address-using-bing-maps
        var request = new GeocodeRequest();
        request.BingMapsKey = "Gr8GooglyMoogly";
        request.Query = fullAddress;

        var result = await request.Execute();
        if (result.StatusCode == 200)
        {
            var toolkitLocation = (result?.ResourceSets?.FirstOrDefault())
                    ?.Resources?.FirstOrDefault()
                    as BingMapsRESTToolkit.Location;
            var _latitude = toolkitLocation.Point.Coordinates[0];
            var _longitude = toolkitLocation.Point.Coordinates[1];
            var mapLocation = new Microsoft.Maps.MapControl.WPF.Location(_latitude, _longitude);
            this.Pins.Add(new Pushpin() 
            { 
                Location = mapLocation,
                ToolTip = String.Format("{0}{1}{2}{1}{3},{4}{1}{5}", location, Environment.NewLine, fullAddress, _latitude,                         _longitude, mapDetailNotes),
                Content = iContentCounter 
            });
            UpdateLocationWithCoordinates(location, _latitude, _longitude);
        }
    }
}

在我看来，无论是从文件创建 map 还是从数据库加载 map ，创建 Pin 图然后在 map 中显示它们的代码都是相同的。那么为什么行为不同呢？
更新
举一个更具体的例子，当通过包含如下内容的文件(前几行的摘录)创建 map 时:

July 15 & 16, 1895 - Music Hall, Cleveland, Ohio;; Cleveland;Ohio;44101
July 18, 1895 - Soo Opera House or Hotel Iroquois, Sault Ste. Marie, Michigan;;Sault Ste. Marie;Michigan;49783
July 19, 1895 - Casino Room, Grand Hotel, Mackinac, Michigan;;Mackinac;Michigan;49757
July 20, 1895 - Grand Opera House, Petoskey, Michigan;;Petoskey;Michigan;49770
July 22, 1895 - First Methodist Church, Duluth, Minnesota;;Duluth;Minnesota;55802
July 23, 1895 - Hotel West & Reception and Supper, Minneapolis, Minnesota;;Minneapolis;Minnesota;55111
July 24, 1895 - People's Church, St. Paul, Minnesota;;St. Paul;Minnesota;55101
July 27, 1895 - Luncheon and Manitoba Club Supper, Winnipeg, Canada;;Winnipeg;Canada;R0G 0A1

...我一开始就得到了这个(只有一个子集，并且所有这些都具有相同的内容编号):

...但是当我此后立即通过“加载现有”加载 map 时，我得到了一切:

?
更新 2
感谢“The Bing Maps Whisperer”，Reza Aghaei，它现在可以工作了:

Answer 1

以下是我认为您需要应用的修复程序:

更改 AddPushpin签名到 async Task AddPushpin(...)

然后在 InsertMapDetailRecord将调用更改为 await AddPushpin(...);

更改 InsertMapDetailRecord签名到 async Task InsertMapDetailRecord(...)

更改 btnOpenTSVFile_Click签名到 async void btnOpenTSVFile_Click

然后在 btnOpenTSVFile_Click换电话 InsertMapDetailRecord至 await InsertMapDetailRecord()

我也猜你应该:

在 AddPushpin方法，删除 this.DialogResult = DialogResult.OK;

在 btnOpenTSVFile_Click , 添加 this.DialogResult = DialogResult.OK;在 while 循环结束之后。

使用异步/等待
基本上在方法中时 void M(...)你想调用一个方法 DoSomething(...)返回 Task ，将调用更改为 await DoSomething(...); .然后如果方法 M是一个事件处理器，把签名改成 async void M(...) , 否则如果是正常方法，则将签名更改为 async Task M(...) .
设置 DialogResult
我认为您需要更改签名以及设置对话框结果的行的原因:在 AddPushpin , 您正在设置 DialogResult OK，这意味着在添加第一个图钉后，包含对话框( mdlDlgCreateMapAndLocsFromTSVFile )将关闭，您开始查看 Pins 属性(仍在场景后面被填充，然后在添加前几个图钉后有机会被添加到 Pins 属性，您处理 mdlDlgCreateMapAndLocsFromTSVFile 并且不会再向 map 添加图钉。
变量范围
我们没有看到整个代码，但要注意变量/字段的范围。作为警告，在整个方法中访问类字段不是一个好主意，它们不是局部变量，当您更改这些值时，其他方法也可以看到更改。