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在日常开发中,DataGrid作为二维表格,非常适合数据的展示和统计。通常情况下,一般都有固定的格式和确定的数据列展示,但是在某些特殊情况下,也可能会需要用到动态生成列。本文以一些简单的小例子,简述在WPF开发中,如何动态生成DataGrid的行和列,仅供学习分享使用,如有不足之处,还请指正。
涉及知识点
在本示例中,用到的知识点如下所示:
- CommunityToolkit.Mvvm,微软提供的一个基于.Net的MVVM框架库,通过此库,可以方便是实现数据绑定和命令绑定,达到前后端分离的目的。
- ObservableCollection ,相比较于List,当列表中的数据条数发生变化时,会自动进行通知,实现数据的实时更新。
- DataTable,表示内存的一个数据表格,可以动态创建列,并自动绑定到DataGrid中。
- ExpandoObject 表示一个动态对象,其内容可以动态添加和删除。
普通绑定
将ViewModel中的列表对象,绑定到View页面中的DataGrid,实现步骤如下:
1. 创建模型
创建绑定到DataGrid中的对象模型,如下所示:- public class Student
- {
- /// <summary>
- /// 唯一标识
- /// </summary>
- public int Id { get; set; }
- /// <summary>
- /// 姓名
- /// </summary>
- public string Name { get; set; }
- /// <summary>
- /// 年龄
- /// </summary>
- public int Age { get; set; }
- /// <summary>
- /// 性别
- /// </summary>
- public string Gender { get; set; }
- /// <summary>
- /// 地址
- /// </summary>
- public string Addr { get; set; }
- }
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2. 创建数据源列表对象
创建要绑定到视图层的列表对象Students,并赋值,如下所示:- public class GeneralBindingViewModel:ObservableObject
- {
- private ObservableCollection<Student> students;
- public ObservableCollection<Student> Students
- {
- get { return students; }
- set { SetProperty(ref students, value); }
- }
- public GeneralBindingViewModel()
- {
- Students=new ObservableCollection<Student>();
- }
- #region Loaded命令
- private ICommand winLoadedCommand;
- public ICommand WinLoadedCommand
- {
- get
- {
- if (winLoadedCommand == null)
- {
- winLoadedCommand = new RelayCommand<object>(WinLoaded);
- }
- return winLoadedCommand;
- }
- }
- private void WinLoaded(object sender)
- {
- if (sender != null)
- {
- }
- if (Students == null || Students.Count < 1)
- {
- var parentName = new string[5] { "张", "王", "李", "赵", "刘" };
- var province = new string[5] { "河南", "江苏", "河北", "湖北", "福建" };
- for (int i = 0; i < 20; i++)
- {
- var student = new Student()
- {
- Id = i,
- Name = parentName[(i % 4)] + i.ToString().PadLeft(2, 'A'),
- Age = 20 + (i % 5),
- Gender = i % 2 == 0 ? "男" : "女",
- Addr = province[(i % 4)]
- };
- this.Students.Add(student);
- }
- }
- }
- #endregion
- }
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3. 视图绑定
在UI视图中,为DataGrid的ItemsSource属性绑定数据源,如下所示:- <Window x:
- xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
- xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
- xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
- xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
- xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
- xmlns:local="clr-namespace:DemoDynamicBinding"
- mc:Ignorable="d"
- Title="基础绑定" Height="450" Width="800">
- <i:Interaction.Triggers>
- <i:EventTrigger EventName="Loaded">
- <i:InvokeCommandAction Command="{Binding WinLoadedCommand}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}"/>
- </i:EventTrigger>
- </i:Interaction.Triggers>
- <Grid>
- <DataGrid ItemsSource="{Binding Students}" CanUserAddRows="False" CanUserDeleteRows="False" ColumnWidth="*" ColumnHeaderHeight="30" RowHeight="25" AlternationCount="2" AlternatingRowBackground="AliceBlue" RowBackground="#ffffee">
-
- </DataGrid>
- </Grid>
- </Window>
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4. 关联视图层和ViewModel层
在视图文件对应的cs文件中,创建ViewModel对象,如下所示:- public partial class GeneralBinding : Window
- {
- private GeneralBindingViewModel viewModel;
- public GeneralBinding()
- {
- InitializeComponent();
- if(viewModel == null)
- {
- viewModel = new GeneralBindingViewModel();
- this.DataContext = viewModel;
- }
- }
- }
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动态生成列
在WPF开发中,动态生成DataGrid列,共有两种方式:
1. DataTable作为数据源
通过DataTable作为数据源,可以不用创建模型,也不需要使用ObservableCollection对象,直接使用DataTable作为数据承载对象,DataGrid会根据DataTable的Columns列表自动生成列。如下所示:- public class DataTableBindingViewModel:ObservableObject
- {
- private DataTable students;
- public DataTable Students
- {
- get { return students; }
- set { SetProperty(ref students , value); }
- }
- public DataTableBindingViewModel()
- {
- Students = new DataTable();
- }
- #region Loaded命令
- private ICommand winLoadedCommand;
- public ICommand WinLoadedCommand
- {
- get
- {
- if (winLoadedCommand == null)
- {
- winLoadedCommand = new RelayCommand<object>(WinLoaded);
- }
- return winLoadedCommand;
- }
- }
- private void WinLoaded(object sender)
- {
- if (sender != null)
- {
- }
- if (Students == null || Students.Rows.Count < 1)
- {
- var students = new DataTable();
- students.Columns.Add("Id",typeof(int));
- students.Columns.Add("Name", typeof(string));
- students.Columns.Add("Age", typeof(int));
- students.Columns.Add("Gender", typeof(string));
- students.Columns.Add("Addr", typeof(string));
- var parentName = new string[5] { "张", "王", "李", "赵", "刘" };
- var province = new string[5] { "河南", "江苏", "河北", "湖北", "福建" };
-
- for (int i = 0; i < 20; i++)
- {
- var dr = students.NewRow();
- dr["Id"] = i;
- dr["Name"] = parentName[(i % 5)] + i.ToString().PadLeft(2, 'A');
- dr["Age"] = 20 + (i % 5);
- dr["Gender"] = i % 2 == 0 ? "男" : "女";
- dr["Addr"] = province[(i % 5)];
-
- students.Rows.Add(dr);
- }
- this.Students= students;
- }
- }
- #endregion
- }
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2. ExpandoObject作为模型
ExpandoObject是dynamic类型,可以在运行时动态的添加和删除内容。而且ExpandoObject对象支持Key=Value形式,并可以对Key进行绑定。如下所示:- public class DynamicBindingViewModel : ObservableObject
- {
- private ObservableCollection<ExpandoObject> students;
- public ObservableCollection<ExpandoObject> Students
- {
- get { return students; }
- set { SetProperty(ref students , value); }
- }
- private DataGrid dataGrid;
- public DynamicBindingViewModel()
- {
- this.Students = new ObservableCollection<ExpandoObject>();
- }
- #region Loaded命令
- private ICommand winLoadedCommand;
- public ICommand WinLoadedCommand
- {
- get
- {
- if (winLoadedCommand == null)
- {
- winLoadedCommand = new RelayCommand<object>(WinLoaded);
- }
- return winLoadedCommand;
- }
- }
- private void WinLoaded(object sender)
- {
- if (sender != null)
- {
- var control = sender as DynamicBinding;
- if (control != null)
- {
- this.dataGrid = control.dgTest;
- }
- }
- if (Students == null || Students.Count < 1)
- {
- var parentName = new string[5] { "张", "王", "李", "赵", "刘" };
- var province = new string[5] { "河南", "江苏", "河北", "湖北", "福建" };
- for (int i = 0; i < 20; i++)
- {
- dynamic item = new ExpandoObject();
- item.Id=i.ToString();
- item.Name = parentName[(i % 5)] + i.ToString().PadLeft(2, 'A');
- item.Age = 20 + (i % 5);
- item.Gender = i % 2 == 0 ? "男" : "女";
- item.Addr = province[(i % 5)];
- this.Students.Add(item);
- }
- //添加列
- this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "学号", Binding = new Binding("Id") });
- this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "姓名", Binding = new Binding("Name") });
- this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "年龄", Binding = new Binding("Age") });
- this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "性别", Binding = new Binding("Gender") });
- this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "地址", Binding = new Binding("Addr") });
- }
- }
- #endregion
- }
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示例效果
以上三种方式,实现的效果都是一致的,只是分别应用到不同的场景中,如下所示:
源码下载
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