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：
1.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。
2.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。
3.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。
4.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; }
}
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
}
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:Class="DemoDynamicBinding.GeneralBinding"
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>
4. 关联视图层和ViewModel层
在视图文件对应的cs文件中，创建ViewModel对象实例并赋值给视图的DataContext属性，如下所示：
public partial class GeneralBinding : Window
{
private GeneralBindingViewModel viewModel;
public GeneralBinding()
{
InitializeComponent();
if(viewModel == null)
{
viewModel = new GeneralBindingViewModel();
this.DataContext = viewModel;
}
}
}
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
}
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。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
}
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：
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