Gridview更改事件未触发以及如何在插入记录后刷新网格？

Question

我试图通过MVVM模式获得WPF技能。我几乎完成了基本功能，但面临2个问题

1）我的Gridview更改事件未触发 2）如何在插入记录后刷新网格

我的ViewModel和View代码如下所示

查看模型

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows.Input;
using DatabaseLayer;
using System.Data;

namespace WPFnMVVM.ViewModel 
{
    public class ContactsViewModel : WPFnMVVM.Common.VMBase
    {
        #region Variables
        private int _Id;
        private string _First_Name;
        private string _Last_Name;
        private DateTime _DOB;
        private clstbl_Contacts _Contacts;
        public WPFnMVVM.Common.RelayCommand _addCommand;
        public DataTable _tblContacts;
        #endregion

        public ContactsViewModel()
        {

            _tblContacts = LoadContacts();
        }


        #region Public Properties
        public int Id
        {
            get { return _Id; }
            set { _Id = value; OnPropertyChanged("Id"); }
        }
        public string First_Name
        {
            get { return _First_Name; }
            set { _First_Name = value; OnPropertyChanged("First_Name"); }
        }
        public string Last_Name
        {
            get { return _Last_Name; }
            set { _Last_Name = value; OnPropertyChanged("Last_Name"); }
        }
        public DateTime DOB
        {
            get { return _DOB; }
            set { _DOB = value; OnPropertyChanged("DOB"); }
        }
        public clstbl_Contacts Contacts
        {
            get { return _Contacts; }
            set
            {
                _Contacts = value;
                OnPropertyChanged("Contacts");
            }


        }

        public DataTable ContactsList
        {
            get { return _tblContacts; }
            set
            {
                _tblContacts = value;
                OnPropertyChanged("ContactsList");
            }
        }
        #endregion

        #region Private Methods
        private DataTable LoadContacts()
        {
            clstbl_Contacts objContact = new clstbl_Contacts(WPFnMVVM.Common.clsSettings.ConStr);
            {
                return objContact.Select();


            };
        }

        private void AddContacts()
        {
            clstbl_Contacts objContacts = new clstbl_Contacts(WPFnMVVM.Common.clsSettings.ConStr);
            objContacts.First_Name = First_Name;
            objContacts.Last_Name = Last_Name;
            objContacts.DOB = DOB;
            objContacts.Insert();
        }

        #endregion

        #region Commands
          public ICommand AddCommand
        {
            get
            {
                if (_addCommand == null)
                {
                    _addCommand = new WPFnMVVM.Common.RelayCommand(
                        param => this.AddContacts(),
                        param => true
                        );
                }
                return _addCommand;
            }
        }
        #endregion

    }
}

查看

<Window x:Class="WPFnMVVM.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:VM="clr-namespace:WPFnMVVM.ViewModel"
        xmlns:View="clr-namespace:WPFnMVVM"
        Title="MainWindow" Height="350" Width="337">
    <Window.DataContext>
        <VM:ContactsViewModel/>
    </Window.DataContext>
    <Grid Name="MyGrid">
        <TextBox HorizontalAlignment="Left" Height="23" Margin="95,13,0,0" TextWrapping="Wrap" Text="{Binding Path=First_Name, UpdateSourceTrigger=PropertyChanged}"  VerticalAlignment="Top" Width="120" />
        <TextBox HorizontalAlignment="Left" Height="23" Margin="95,47,0,0" TextWrapping="Wrap" Text="{Binding Path=Last_Name, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Top" Width="120"/>
        <Label Content="First Name" HorizontalAlignment="Left" Margin="8,10,0,0" VerticalAlignment="Top"/>
        <Label Content="Last Name" HorizontalAlignment="Left" Margin="9,47,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.68,1.974"/>
        <Label Content="DOB" HorizontalAlignment="Left" Margin="8,75,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.68,1.974"/>
        <DatePicker Height="25" HorizontalAlignment="Left" Margin="95,76,0,0" Name="datePicker1"
            VerticalAlignment="Top" Width="120" SelectedDate="{Binding Path=DOB, UpdateSourceTrigger=PropertyChanged}"/>
        <Button Content="Add" HorizontalAlignment="Left" Margin="9,118,0,0" VerticalAlignment="Top" Width="75" Command="{Binding Path=AddCommand}"/>
        <Button Content="Update" HorizontalAlignment="Left" Margin="102,118,0,0" VerticalAlignment="Top" Width="75"/>
        <Button Content="Delete" HorizontalAlignment="Left" Margin="193,118,0,0" VerticalAlignment="Top" Width="75"/>
        <ListView BorderBrush="White" ItemsSource="{Binding Path=ContactsList, UpdateSourceTrigger=PropertyChanged}"
                   HorizontalAlignment="Stretch" Margin="11,156,10,10" SelectedValue="{Binding Path=Contacts, UpdateSourceTrigger=PropertyChanged}">
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="First Name" 
                                    DisplayMemberBinding="{Binding Path=First_Name}" Width="70" />
                    <GridViewColumn Header="Last Name"
                                    DisplayMemberBinding="{Binding Path=Last_Name}" Width="70" />
                    <GridViewColumn Header="DOB" 
                                    DisplayMemberBinding="{Binding Path=DOB}" Width="70" />

                </GridView>
            </ListView.View>
        </ListView >

    </Grid>
</Window>

如果可能的话，请指导并给我参考sql crud函数的任何实际应用程序，我可以从中提高我的技能。

由于

Answer 1

DataTable没有实现INotifyPropertyChanged，因此您将遇到直接绑定到它的问题。您将看到初始数据，但随后数据的更改将不会反映在视图中。

我认为最简单的选择是使用DataView， 实现INotifyPropertyChanged。您可以使用_tblContacts.DefaultView轻松获取桌面视图。

Answer 2

@Rob H，我改变了我的逻辑有点好思考现在我正在获取我的值并记录插入但现在唯一的问题是gridview在插入记录后没有刷新。

请查看以下代码。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows.Input;
using DatabaseLayer;
using System.Data;

namespace WPFnMVVM.ViewModel 
{
    public class ContactsViewModel : WPFnMVVM.Common.VMBase
    {
        #region Variables
        private int _Id;
        private string _First_Name;
        private string _Last_Name;
        private DateTime _DOB;
        private clstbl_Contacts _Contacts;
        public WPFnMVVM.Common.RelayCommand _addCommand;
        public ObservableCollection<clstbl_Contacts> _ContactsList;
        #endregion

        #region Contructor
        public ContactsViewModel()
        {
            LoadContacts();
        }      
        #endregion

        #region Public Properties
        public int Id
        {
            get { return _Id; }
            set { _Id = value; OnPropertyChanged("Id"); }
        }
        public string First_Name
        {
            get { return _First_Name; }
            set { _First_Name = value;

                OnPropertyChanged("First_Name"); }
        }
        public string Last_Name
        {
            get { return _Last_Name; }
            set { _Last_Name = value; OnPropertyChanged("Last_Name"); }
        }
        public DateTime DOB
        {
            get { return _DOB; }
            set { _DOB = value; OnPropertyChanged("DOB"); }
        }
        public clstbl_Contacts Contacts
        {
            get { return _Contacts; }
            set
            {
                _Contacts = value;

                OnPropertyChanged("Contacts");
                GetValuesFromModel();
            }


        }
        public ObservableCollection<clstbl_Contacts> ContactsList
        {
            get { return _ContactsList; }
            set
            {
                _ContactsList = value;
                OnPropertyChanged("ContactsList");
            }
        }     
        #endregion

        #region Methods
        private void LoadContacts()
        {

            clstbl_Contacts objContact = new clstbl_Contacts(WPFnMVVM.Common.clsSettings.ConStr);
            DataTable dt = objContact.Select();
            _ContactsList = new ObservableCollection<clstbl_Contacts>();

            for (int i = 0; i < dt.Rows.Count; i++)
            {
                _ContactsList.Add(new clstbl_Contacts { Id = Convert.ToInt16(dt.Rows[i]["ID"].ToString())
                                                        ,First_Name = dt.Rows[i]["First_Name"].ToString(),
                                                        Last_Name = dt.Rows[i]["Last_Name"].ToString(),
                                                        DOB = Convert.ToDateTime(dt.Rows[i]["DOB"].ToString())
                });
            }

        }
        private void AddContacts()
        {
            clstbl_Contacts objContacts = new clstbl_Contacts(WPFnMVVM.Common.clsSettings.ConStr);
            objContacts.First_Name = First_Name;
            objContacts.Last_Name = Last_Name;
            objContacts.DOB = DOB;
            objContacts.Insert();

        }

        private void GetValuesFromModel()
        {
            Id = _Contacts.Id;
            First_Name = _Contacts.First_Name;
            Last_Name = _Contacts.Last_Name;
            DOB = _Contacts.DOB;
        }
        #endregion

        #region Commands
          public ICommand AddCommand
        {
            get
            {
                if (_addCommand == null)
                {
                    _addCommand = new WPFnMVVM.Common.RelayCommand(
                        param => this.AddContacts(),
                        param => true
                        );
                }
                return _addCommand;
            }
        }
        #endregion

    }
}

查看

<Window x:Class="WPFnMVVM.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:VM="clr-namespace:WPFnMVVM.ViewModel"
        xmlns:View="clr-namespace:WPFnMVVM"

        Title="MainWindow" Height="350" Width="337">
    <Window.DataContext>
        <VM:ContactsViewModel/>
    </Window.DataContext>
    <Grid Name="MyGrid">
        <TextBox HorizontalAlignment="Left" Height="23" Margin="95,13,0,0" TextWrapping="Wrap" 
                 Text="{Binding Path=First_Name, UpdateSourceTrigger=PropertyChanged}"   VerticalAlignment="Top" Width="120" />

        <TextBox HorizontalAlignment="Left" Height="23" Margin="95,47,0,0" TextWrapping="Wrap" Text="{Binding Path=Last_Name, ValidatesOnDataErrors=True, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Top" Width="120"/>
        <Label Content="First Name" HorizontalAlignment="Left" Margin="8,10,0,0" VerticalAlignment="Top"/>
        <Label Content="Last Name" HorizontalAlignment="Left" Margin="9,47,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.68,1.974"/>
        <Label Content="DOB" HorizontalAlignment="Left" Margin="8,75,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.68,1.974"/>
        <DatePicker Height="25" HorizontalAlignment="Left" Margin="95,76,0,0" Name="datePicker1"
            VerticalAlignment="Top" Width="120" SelectedDate="{Binding Path=DOB, UpdateSourceTrigger=PropertyChanged}"/>
        <Button Content="Add" HorizontalAlignment="Left" Margin="9,118,0,0" VerticalAlignment="Top" Width="75" Command="{Binding Path=AddCommand}"/>
        <Button Content="Update" HorizontalAlignment="Left" Margin="102,118,0,0" VerticalAlignment="Top" Width="75"/>
        <Button Content="Delete" HorizontalAlignment="Left" Margin="193,118,0,0" VerticalAlignment="Top" Width="75"/>
        <ListView BorderBrush="White" ItemsSource="{Binding Path=ContactsList, UpdateSourceTrigger=PropertyChanged}"
                   HorizontalAlignment="Stretch" Margin="11,156,10,10" SelectedValue="{Binding Path=Contacts, UpdateSourceTrigger=PropertyChanged}">
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="First Name" 
                                    DisplayMemberBinding="{Binding Path=First_Name}" Width="70" />
                    <GridViewColumn Header="Last Name"
                                    DisplayMemberBinding="{Binding Path=Last_Name}" Width="70" />
                    <GridViewColumn Header="DOB" 
                                    DisplayMemberBinding="{Binding Path=DOB}" Width="70" />

                </GridView>
            </ListView.View>
        </ListView >

    </Grid>
</Window>