的视图模型

Question

我试图通过从两个组合框中选择两个值来过滤dataGrid，但是所选的值会将值0发送到属性。

var idShop = Shop;等于零

var idSupplier = Supplier;等于零

的视图模型

public class ConsultInvoiceViewModel:ViewModelBase
    {
        public Context ctx = new tContext();

        private ICollectionView _dataGridCollection;
        private string _filterString;
        private ObservableCollection<Invoice> invoiceCollection = new ObservableCollection<Invoice>();


        public ConsultInvoiceViewModel()
        {
            DataGridCollection = CollectionViewSource.GetDefaultView(Get());
            //DataGridCollection.Filter = new Predicate<object>(Filter);
        }

        public ICollectionView DataGridCollection
        {
            get
            { 
                return _dataGridCollection; 
            }
            set 
            { 
                _dataGridCollection = value; 
                OnPropertyChanged("DataGridCollection"); }
        }


        private void FilterCollection()
        {
            if (_dataGridCollection != null)
            {
                _dataGridCollection.Refresh();
            }
        }




        private void Search()
        {
            var idShop = Shop;
            var idSupplier = Supplier;

            var inv = (from i in ctx.Invoices
                       where i.shop == idShop 
                       && i.supplier == idSupplier
                       select i).SingleOrDefault();

            invoiceCollection.Clear();
            invoiceCollection.Add(inv);
            FilterCollection();

        }

        private ObservableCollection<Invoice> Get()
        {
            ctx.Invoices.ToList().ForEach(invoice => ctx.Invoices.Local.Add(invoice));
            invoiceCollection = ctx.Invoices.Local;
            return invoiceCollection;
        }
        private void GetShop()
        {
            ctx.shops.ToList().ForEach(shop => ctx.shops.Local.Add(shop));
            SShop = ctx.shops.Local;
        }

        private void GetSupplier()
        {
            ctx.foodSuppliers.ToList().ForEach(supplier => ctx.foodSuppliers.Local.Add(supplier));
            FoodSupplier = ctx.foodSuppliers.Local;
        }

        private IList<foodSupplier> supplier;

        public IList<foodSupplier> FoodSupplier
        {
            get
            {
                if (supplier == null)
                GetSupplier();
                return supplier;
            }
            set
            {
                supplier = value;
                OnPropertyChanged("FoodSupplier");
            }
        }

        private IList<shop> shop;

        public IList<shop> SShop
        {
            get
            {
                if(shop == null)
                GetShop();
                return shop;
            }
            set
            {
                shop = value;
                OnPropertyChanged("SShop");
            }
        }

        private int _shop;

        public int Shop
        {
            get 
            { 
                return _shop; 
            }
            set 
            {
                _shop = value;
                OnPropertyChanged("Shop");
            }
        }

        private int _supplier;

        public int Supplier
        {
            get
            {
                return _supplier;
            }
            set
            {
                _supplier = value;
                OnPropertyChanged("Supplier");
            }
        }





        #region "Command"

        private ICommand searchCommand;


        public ICommand SearchCommand
        {
            get
            {
                return searchCommand ?? (searchCommand = new RelayCommand(p => this.Search(), p => this.CanSearch()));
            }
        }

        private bool CanSearch()
        {
           if (Supplier != 0 && Shop != 0)
                return true;
            else
                return false;

        }

        #endregion
    }

查看

<StackPanel Orientation="Horizontal">
                <Label Content="Shop"/>
                <ComboBox Name="shopComboBox"
                          Margin="5" 
                          ItemsSource="{Binding SShop}" 
                          DisplayMemberPath="shop1" Width="73"
                          SelectedItem="{Binding Shop, Mode=OneWayToSource}" 
                          SelectedValuePath="idshop" SelectionChanged="shopComboBox_SelectionChanged"/>
                <Label Content="Supplier"/>
                <ComboBox Name="supplierComboBox"
                          Margin="5" 
                          ItemsSource="{Binding FoodSupplier}" 
                          DisplayMemberPath="supplier"
                          SelectedItem="{Binding Supplier, Mode=OneWayToSource}" 
                          SelectedValuePath="idfoodSupplier"
                          Width="71"/>
                <Label Content="Shop"/>
                <Button Content="Search" 
                            Margin="5"
                            Command="{Binding SearchCommand}"/>
            </StackPanel>


            <StackPanel Orientation="Vertical">
                <DataGrid Margin="5" ItemsSource="{Binding DataGridCollection}" AutoGenerateColumns="False" >
                    <DataGrid.Columns>
                        <DataGridTextColumn Header="SuppNb" Binding="{Binding suppInvNumber}" Width="*"/>
                        <DataGridTextColumn Header="Shop" Binding="{Binding shop1.shop1}" Width="*"/>
                        <DataGridTextColumn Header="Date" Binding="{Binding date}" Width="*"/>
                        <DataGridTextColumn Header="Supplier" Binding="{Binding foodSupplier.supplier}" Width="*"/>
                        <DataGridTextColumn Header="Ref Supplier" Binding="{Binding refSupp}" Width="*"/>
                        <DataGridTextColumn Header="Unit" Binding="{Binding unit}" Width="*"/>
                        <DataGridTextColumn Header="Quantity" Binding="{Binding quantity}" Width="*"/>
                        <DataGridTextColumn Header="Prix/MOQ" Binding="{Binding unitPrice}" Width="*"/>
                        <DataGridTextColumn Header="Total Price" Binding="{Binding totalPrice}" Width="*"/>
                    </DataGrid.Columns>
                </DataGrid>
            </StackPanel>

Answer 1

在SelectedItem上绑定是错误的。请将SelectedValue与SelectedValuePath一起使用。

SelectedItem只能绑定到项目（对象）。而SelectedValue可以绑定到项目的SelectedValuePath指定的值。

只需像下面一样进行更改，您就可以从组合框中获得结果。

            <ComboBox Name="supplierComboBox"
                      Margin="5" 
                      ItemsSource="{Binding FoodSupplier}" 
                      DisplayMemberPath="supplier"
                      SelectedValue="{Binding Supplier, Mode=OneWayToSource}" 
                      SelectedValuePath="idfoodSupplier"
                      Width="71"/>

Answer 2

您需要将Comoboxes绑定到ViewModel中的某个命令，以便ViewModel知道您选择了什么？

或者，您需要将ComboBoxes选定的项目作为参数传递给搜索命令，以便在您的搜索方法中可以访问用户选择的值。

现在你正在直接访问Shop，这是毫无意义的。您假设当您在ShopComboBox中选择项目时，ViewModel中的Shop变量将获得该值。这是错误的。

当您将ObservableCollection绑定到DataGrid，并在DataGrid中选择一行时，ObservableCollection不知道有关此选择的任何内容，但您的DataGrid会这样做。

来自combobox的dataGrid过滤器不起作用

的视图模型

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2 个答案: