为什么 DataGridComboBoxColumn 的默认值没有出现在 C# WPF 中的 DataGrid 中？

Question

项目主题： 我有一个连接到 SQL Server 数据库的 MS Access 2003 adp VBA 项目，现在我正在将该项目转换为 C# WPF，并且我打算将数据从 C# WPF 中的 DataGrid 直接保存到 SQL Server 数据库

细节： 我有 DataGrid，ItemsSource 绑定到名为“INVO_DATA_RASID_KHARID”的“ObservableCollection”以及名为“ANBAR_COLUMN”的“DataGridComboBoxColumn”，此“DataGridComboBoxColumn”的“ItemSource”通过 SQL Server 填充。

我希望此“DataGridComboBoxColumn”以默认值显示，以便用户知道无需从“DataGridComboBoxColumn”列表中手动选择它。

我通过这个名为“FillALLComboboxes”的方法后面的代码中的静态变量设置这个默认值。

问题：考虑到DataGrid中的'DataGridComboBoxColumn'，'ANBAR_COL''DataGridComboBoxColumn'有一个默认值，用户不需要从'DataGridComboBoxColumn'列表中手动选择那个项目，但只要他们加倍-点击'ANBAR_COL'组合框单元格，默认值就会出现！ 重点是为“DataGridComboBoxColumn”设置的默认值在用户输入单元格之前不会显示！

XAML：

        <DataGrid   x:Name="INVO_LST_RASID_SUB"
                        EnableColumnVirtualization="True"
                        EnableRowVirtualization="True"
                        VirtualizingPanel.IsVirtualizing="True"
                        VirtualizingPanel.VirtualizationMode="Recycling"
                        ScrollViewer.CanContentScroll="False"
                    
                        KeyboardNavigation.TabNavigation="Contained"
                        ItemsSource="{Binding INVO_DATA_RASID_KHARID}"
                        Grid.Row="5"
                        Margin="5,10"
                        AutoGenerateColumns="False"  FlowDirection="RightToLeft"  SelectionUnit="FullRow"   BorderThickness="1" >
       
            <DataGrid.Columns>

                <DataGridComboBoxColumn x:Name="ANBAR_COLUMN" MinWidth="80" Width="auto" Header=" انبار " 
                                        SelectedValueBinding="{Binding ANBAR,UpdateSourceTrigger=PropertyChanged}"
                                        DisplayMemberPath="NAMES" SelectedValuePath="CODE">
                    <DataGridComboBoxColumn.EditingElementStyle>
                        <Style TargetType="{x:Type ComboBox}">
                            <Setter Property="IsEditable" Value="True"/>
                        </Style>
                    </DataGridComboBoxColumn.EditingElementStyle>

                </DataGridComboBoxColumn>
       
            </DataGrid.Columns>
        </DataGrid>

我的窗口后面的代码（C#）：

//MainWindow:
    public partial class HEAD_LST_RASID : Window
    {
        public ObservableCollection<INVO_LST_RASID_KHARID_CSHARP> INVO_DATA_RASID_KHARID { get; set; } = new ObservableCollection<INVO_LST_RASID_KHARID_CSHARP>();

        public HEAD_LST_RASID()
        {
            InitializeComponent();
            this.DataContext = this;
        }
        public void FillALLComboboxes()
        {
            string RowSource_ANBAR = "SELECT    CODE, NAMES FROM  dbo.TCOD_ANBAR";
            //Search for the default value if it exists
            var rst = dbms.Database.SqlQuery<int?>("SELECT     ANBCO FROM dbo.OPANBACCESS WHERE     (USERCO = " + Baseknow.USERCOD + " ) ORDER BY dbo.OPANBACCESS.RDF").ToList();
            if (rst.Count > 0)
            {
                Baseknow.anbardef = (int)rst.FirstOrDefault();
            }
            var ARST = dbms.Database.SqlQuery<Custom_TCODANBAR>(RowSource_ANBAR).ToList();
            ANBAR_COLUMN.ItemsSource = ARST;
        }
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            FillALLComboboxes();
            
              var QRE_LST = dbms.Database.SqlQuery<INVO_LST_RASID_KHARID_CSHARP>($@"SELECT * FROM INVOICES").ToList();
              INVO_DATA_RASID_KHARID?.Clear();
              
                foreach (var item in QRE_LST)
                    INVO_DATA_RASID_KHARID.Add(item);
        }
    }

模特班：

//Model:
    public class CTABLES
    {
        public class INVO_LST_RASID_KHARID_CSHARP : INotifyPropertyChanged, ICloneable
        {
            public object Clone()
            {
                return this.MemberwiseClone();
            }
        
            public INVO_LST_RASID_KHARID_CSHARP()
            {
                ANBAR = Baseknow.anbardef;
            }

            private int? _anbar;
            public int? ANBAR
            {
                get
                {
                    return _anbar;
                }
                set
                {
                    if (_anbar == value)
                        return;
                    _anbar = value;
                    OnPropertyChanged("ANBAR");
                }
            }

            public event PropertyChangedEventHandler PropertyChanged;
            protected virtual void OnPropertyChanged(string propertyName = "")
            {
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

我想要的是在加载“DataGrid”数据时显示已为“DataGrid”中的此组合框选择了默认值（无需双击并进入CellEditing模式）。

Answer 1

我绕过了我的问题并且成功了！ :

XAML：

  <DataGridComboBoxColumn x:Name="ANBAR_COLUMN" 
                                        DisplayMemberPath="NAMES" SelectedValuePath="CODE"
                                        SelectedValueBinding="{Binding ANBAR,UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}"
                                        MinWidth="80" Width="auto" Header=" انبار " 
                                        >
                    <DataGridComboBoxColumn.EditingElementStyle>
                        <Style TargetType="{x:Type ComboBox}">
                            <Setter Property="IsEditable" Value="True"/>
                        </Style>
                    </DataGridComboBoxColumn.EditingElementStyle>

                    <DataGridComboBoxColumn.ElementStyle>
                        <Style TargetType="ComboBox">
                            <Setter Property="SelectedIndex" Value="{Binding DefaultValDisplay, Source={StaticResource BoundyAnbar}}"/>
                        </Style>
                    </DataGridComboBoxColumn.ElementStyle>

                </DataGridComboBoxColumn>

C#：

using System.ComponentModel;

namespace WpfApp5.Boundy
{
    public class CL_Boundy : INotifyPropertyChanged
    {
        private int _myPropertyVariable = 0;
        public int DefaultValDisplay
        {
            get { return _myPropertyVariable; }
            set
            {
                _myPropertyVariable = value;
                OnPropertyChanged(nameof(DefaultValDisplay));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        protected virtual void OnPropertyChanged(string propertyName = "")
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}