如何在不同的类中检查WPF元素的属性

我正在遵循一系列不同的例子等，并试图用它们做我自己的事情。

本质上，在我的代码隐藏中，我有一个单独的类。我认为这是用于MVVM的，尽管我几乎不知道这意味着什么（我明白了，但看起来很困惑！）。

不管怎样。。。这是我在一个单独的类（相同的命名空间）中的代码，用于我的WPF表单的代码：

public class ChartViewModel
    {
        public ChartViewModel()
        {
            DataTable dataNames = new DataTable();
            try
            {
                var db = new SQLiteDatabase();
                string query = "SELECT DISTINCT Name FROM Main";
                ...

现在，我在WPF-xaml页面上有一个名为AccountType的文本块。其中的文本可以在三个不同的值之间循环，我需要在此基础上更改上面代码块末尾的字符串查询。如果是一个值，字符串=x。如果是第二个值，则字符串=y等。

类的这一部分用于用数据库中的条目填充组合框。更改该字符串会自动强制组合框更新吗？或者在这之后我会做其他事情吗？

根据要求，这是我的XAML（无论如何都是相关的东西）

<ComboBox x:Name="NameBox" Grid.Row="0" Grid.Column="0" HorizontalAlignment="Center" VerticalAlignment="Center" ItemsSource="{Binding Names}" Width="100" />
<Grid Grid.Row="0" Grid.Column="1">
    <ProgressBar x:Name="AccountTypeProgress" Width="70" Height="20" MouseDown="AccountTypeButton_Click" />
    <TextBlock x:Name="AccountType" Text="Main" VerticalAlignment="Center" HorizontalAlignment="Center" Foreground="#FF252525" FontSize="16" FontWeight="Bold" MouseDown="AccountTypeButton_Click" />
</Grid>

全视图模型

public class ChartViewModel
{
    public ChartViewModel()
    {
        AccountType = "Main";
        DataTable dataNames = new DataTable();
        try
        {
            var db = new SQLiteDatabase();
            string query = "SELECT DISTINCT Name FROM Main";
            dataNames = db.GetDataTable(query);
        }
        catch (Exception fail)
        {
            string error = "The following error has occured:'n'n";
            //error += fail.Message.ToString() + "'n'n";
            //System.Windows.MessageBox.Show(error);
        }
        this.Names = new ObservableCollection<string> { };
        foreach (DataRow row in dataNames.Rows)
        {
            string name = row["Name"].ToString();
            Names.Add(name);
        }

        int x = 42067;
        DataTable datastats = new DataTable();
        try
        {
            var db = new SQLiteDatabase();
            String query = "SELECT * FROM Main WHERE Name = '"9n'"";
            datastats = db.GetDataTable(query);
        }
        catch (Exception fail)
        {
            String error = "The following error has occurred:'n'n";
            //error += fail.Message.ToString() + "'n'n";
            //System.Windows.MessageBox.Show(error);
        }
        this.overall = new List<DataPoint>
        {
            //foreach(DataRow row in datastats.Rows)
            //{
            //}
        };
        foreach (DataRow row in datastats.Rows)
        {
            DateTime sDate = DateTime.Parse(row["Date"].ToString());
            //int date = ((sDate.Year - 1900)) + sDate.Day;
            sDate = sDate.Date;
            double date = sDate.ToOADate() - 1;
            int dateint = Convert.ToInt32(date);
            string sLevel = row["OverallL"].ToString();
            int level = Convert.ToInt32(sLevel);
            this.overall.Add(new DataPoint(date, level));
        }
        this.overall.Add(new DataPoint(42100, 10));
        this.overall.Add(new DataPoint(42110, 10));
        this.Title2 = "Example 2";
        this.Points = new List<DataPoint>
            {
                new DataPoint(x, 4),
                new DataPoint(42077, 13),
                new DataPoint(42087, 15),
                new DataPoint(42097, 16),
                new DataPoint(42107, 12),
                new DataPoint(42117, 12)
            };
        this.Data = new List<DataPoint>
            {
                new DataPoint(42067, 10),
                new DataPoint(42077, 15),
                new DataPoint(42087, 16),
                new DataPoint(42097, 20),
                new DataPoint(42107, 10),
                new DataPoint(42117, 12)
            };
    }

    public string Title2 { get; private set; }
    public IList<DataPoint> Points { get; private set; }
    public IList<DataPoint> Data { get; private set; }
    public IList<DataPoint> overall { get; private set; }
    public ObservableCollection<string> Names { get; private set; }
    private string _AccountType;
    public string AccountType
    {
        get { return _AccountType; }
        set
        {
            _AccountType = value;
            //OnPropertyChanged stuff here.
        }
    }
}

private string _AccountType;
    public string AccountType
    {
        get { return _AccountType; }
        set 
        { 
            _AccountType = value; 
            //OnPropertyChanged stuff here.
        }
    }

<TextBlock Text="{Binding AccountType}" ... />