我是MVVM和Caliburn.Micro的新手。
我已经实现了一个绑定到的DataGrid。<BindableCollection><CustomerModel>
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; }
}
这些数据在启动时从XML文件中加载,也可以通过点击 "保存 "按钮保存到XML文件中,该按钮与方法SaveToXML()和CanSaveToXML()相连。保存和加载都能完美地工作,但是我想让 "保存 "按钮只有在用户编辑了DataGrid的情况下才能启用,否则它应该保持禁用状态。
我试过比较CustomerModel类的当前对象数量和启动时CustomerModel的对象数量。如果数量不同,就应该启用按钮,因为它表明有人输入或删除了一个条目。
public bool CanSaveToXML()
{
if (CustomersOnStartup != Customers.Count())
return true;
else
return false;
}
其中
public BindableCollection<CustomerModel> Customers { get; set; }
问题是Customers.Count()只执行一次,而且在用户启动和添加删除条目后,数字不更新。我知道这可能与
NotifyOfPropertyChange(() => ???)
但我不知道如何使用它与Customers.Count()的对象数量相关。
欢迎提出任何想法。
XAML实现。
<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>
如果你想测试集合的计数,你必须使用后面的一个属性。
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;
}