循环访问主键并检索相应的数据？

Question

我想通过一个SQLite查询循环，并为每个pk发现我想获得列的相应值date。这是我到目前为止。我的dynamictextbox1获取代码而不是日期。

public void createEntry() 
    { 
     var dbPath = Path.Combine(Windows.Storage.ApplicationData.Current.LocalFolder.Path, "data.db"); 

     /*using (var db = new SQLiteConnection(dbPath)) 
     { 
      db.CreateTable<LogEntry>(); 
      db.RunInTransaction(() => 
      { 
       db.Insert(new LogEntry() { date = dateBox.SelectedItem.ToString(), 
              startTime = startTimeBox.SelectedItem.ToString(), 
              endTime = endTimeBox.SelectedItem.ToString(), 
              activity = activityBox.SelectedItem.ToString(), 
              type = typeBox.SelectedItem.ToString() 
       }); 
      }); 
     }*/ 

     //If the database is empty then don't set the listview itemssource to it otherwise you will get an error. 
     using (var db = new SQLiteConnection(dbPath)) 
     { 
      if (db.Table<LogEntry>().Count() > 0) 
      { 
       var query0 = db.Table<LogEntry>().Select(v => v.ID); 
       var query1 = db.Table<LogEntry>().Select(v => v.date.ToString()); 
       var query2 = db.Table<LogEntry>().Select(v => v.startTime.ToString()); 
       var query3 = db.Table<LogEntry>().Select(v => v.endTime.ToString()); 
       var query4 = db.Table<LogEntry>().Select(v => v.activity.ToString()); 
       var query5 = db.Table<LogEntry>().Select(v => v.type.ToString()); 
       foreach (var item0 in query0) 
       { 

        //var dateID = db.Table<LogEntry>().Where(v => v.ID = query0); 

        //Create the controls and populate them. 
        StackPanel dynamicStackPanel0 = new StackPanel(); 
        dynamicStackPanel0.Orientation = Orientation.Horizontal; 

        StackPanel dynamicStackPanel1 = new StackPanel(); 
        StackPanel dynamicStackPanel2 = new StackPanel(); 
        StackPanel dynamicStackPanel3 = new StackPanel(); 

        TextBlock dynamicTextBlock1 = new TextBlock(); 
        var dataID = db.Table<LogEntry>().Where(v => v.ID.Equals(item0)).Select(v => v.date); 
        dynamicTextBlock1.Text = dataID.ToString(); 

        TextBlock dynamicTextBlock2 = new TextBlock(); 
        foreach (var item2 in query2) 
        { 
         dynamicTextBlock2.Text = item2.ToString(); 
        } 

        TextBlock dynamicTextBlock3 = new TextBlock(); 
        foreach (var item3 in query3) 
        { 
         dynamicTextBlock3.Text = item3.ToString(); 
        } 

        TextBlock dynamicTextBlock4 = new TextBlock(); 
        foreach (var item4 in query4) 
        { 
         dynamicTextBlock4.Text = item4.ToString(); 
        } 

        TextBlock dynamicTextBlock5 = new TextBlock(); 
        foreach (var item5 in query5) 
        { 
         dynamicTextBlock5.Text = item5.ToString(); 
        } 

        TextBlock dynamicTextBlock6 = new TextBlock(); 
        dynamicTextBlock6.Text = "Rating 1"; 

        TextBlock dynamicTextBlock7 = new TextBlock(); 
        dynamicTextBlock7.Text = "Rating 2"; 

        TextBlock dynamicTextBlock8 = new TextBlock(); 
        dynamicTextBlock8.Text = "Rating 3"; 

        //Create the entries. 
        dynamicStackPanel1.Children.Add(dynamicTextBlock1); 
        dynamicStackPanel1.Children.Add(dynamicTextBlock2); 
        dynamicStackPanel1.Children.Add(dynamicTextBlock3); 

        dynamicStackPanel2.Children.Add(dynamicTextBlock4); 
        dynamicStackPanel2.Children.Add(dynamicTextBlock5); 

        dynamicStackPanel3.Children.Add(dynamicTextBlock6); 
        dynamicStackPanel3.Children.Add(dynamicTextBlock7); 
        dynamicStackPanel3.Children.Add(dynamicTextBlock8); 

        dynamicStackPanel0.Children.Add(dynamicStackPanel1); 
        dynamicStackPanel0.Children.Add(dynamicStackPanel2); 
        dynamicStackPanel0.Children.Add(dynamicStackPanel3); 

        entryPanel.Items.Add(dynamicStackPanel0); 
       } 
      } 
     } 
    } 

Answer 1

Select给你一个枚举的日期。您需要FirstOrDefault。

var dataID = db.Table<LogEntry>().Where(v => v.ID == item0) 
       .Select(v => v.date).FirstOrDefault(); 
dynamicTextBlock1.Text = dataID.ToString();