Caliburn.Micro MVVM WPF - 当 DataGrid 已被用户编辑时启用按钮，否则禁用它

Question

我是 MVVM 的新手并且 Caliburn.Micro。

我已经实现了一个绑定到 <BindableCollection><CustomerModel> 的 DataGrid，其中 CustomerModel 是：

    public class CustomerModel
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string StreetName { get; set; }
    public int HouseNumber { get; set; }
    public string ApartmentNumber { get; set; }
    public string PostalCode { get; set; }
    public string Town { get; set; }
    public int PhoneNumber { get; set; }
    public string DateOfBirth { get; set; }
    public int Age { get; set; }
}

此数据在启动时从 XML 文件加载，也可以通过单击与方法 SaveTo[=43] 相关联的按钮 "Save" 保存到 XML 文件中=]() 显然是 CanSaveToXML()。保存和加载工作完美，但我只想在用户编辑 DataGrid 时启用 "Save" 按钮，否则它应该保持禁用状态。

我尝试将 CustomerModel class 的当前对象数与启动时 CustomerModel 的对象数进行比较。如果数字不同，它应该启用该按钮，因为它表明有人输入或删除了条目。

        public bool CanSaveToXML()
    {
        if (CustomersOnStartup != Customers.Count())
            return true;
        else
            return false;
    }

哪里

public BindableCollection<CustomerModel> Customers { get; set; }

问题是 Customers.Count() 只执行一次，并且在启动和 adding/deleting 用户输入后数字不会更新。我知道它可能连接到

NotifyOfPropertyChange(() => ???)

但我不知道如何将它与 Customers.Count()

的对象数量相关联

欢迎提出任何想法。

XAML 实施：

    <Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="20"/>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="20"/>

    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="20"/>
        <RowDefinition Height="auto"/>
        <RowDefinition Height="*"/>
        <RowDefinition Height="20"/>
        <RowDefinition Height="20"/>
    </Grid.RowDefinitions>
    <DataGrid Grid.Row="1" Grid.Column="1" x:Name="Customers" AlternatingRowBackground="LightGray"
              AutoGenerateColumns="False">
        <DataGrid.Columns>
            <DataGridTextColumn Header="First Name" Width="auto" Binding="{Binding Path=FirstName, Mode=TwoWay}" />
            <DataGridTextColumn Header="Last Name" Width="auto" Binding="{Binding Path=LastName}" />
            <DataGridTextColumn Header="Street Name" Width="auto" Binding="{Binding Path=StreetName}" />
            <DataGridTextColumn Header="House Number" Width="auto" Binding="{Binding Path=HouseNumber}" />
            <DataGridTextColumn Header="Apartment Number" Width="auto" Binding="{Binding Path=ApartmentNumber}" />
            <DataGridTextColumn Header="Postal Code" Width="auto" Binding="{Binding Path=PostalCode}" />
            <DataGridTextColumn Header="Town" Width="auto" Binding="{Binding Path=Town}" />
            <DataGridTextColumn Header="Phone Number" Width="auto" Binding="{Binding Path=PhoneNumber}" />
            <DataGridTextColumn Header="Date of Birth" Width="auto" Binding="{Binding Path=DateOfBirth}" />
            <DataGridTextColumn Header="Age" Width="auto" Binding="{Binding Path=Age}" IsReadOnly="True"/>
        </DataGrid.Columns>
    </DataGrid>
    <Button x:Name="SaveToXML" Content="Save" Grid.Column="1" Grid.Row="3" Width="50" HorizontalAlignment="Left"/>
</Grid>

Answer 1

如果你想测试集合的计数，你必须使用它后面的属性：

    private int initcount;
    public YourViewModel()//constructor
    {
        RecordNbr = People.Count;
        initcount = RecordNbr;
    }

    //Property whixh follows the number of count
    private int _recordNbr;
    public int RecordNbr
    {
        get => _recordNbr;
        set
        {
            _recordNbr = value;
            NotifyOfPropertyChange(() => RecordNbr);
            NotifyOfPropertyChange(() => CanSaveToXML);
        }
    }

    public void SaveToXML()
    {

    }

    public bool CanSaveToXML
    {
        get => initcount == RecordNbr;
    }

    public void RemoveItem()
    {
       if (People.Count == 0) return;

        People.RemoveAt(0);
        RecordNbr = People.Count;
    }

Caliburn.Micro MVVM WPF - 当 DataGrid 已被用户编辑时启用按钮，否则禁用它

Caliburn.Micro MVVM WPF - enable a button when DataGrid has been edited by the user, otherwise disable it

c#

wpf

mvvm

caliburn.micro