Question

尝试使用BindingList类型的数据源向Infragistic UltraWinGrid添加新行时出现以下错误：

无法添加行：类型＆＃39; System.String＆＃39;上的构造函数找不到

通过网格删除项目工作正常但是，尝试使用网格底部的添加新行时会出现上述错误。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Infragistics.Win.UltraWinGrid;
using Infragistics.Win;

namespace BindingListChangedEvent
{
    public partial class FrmMain : Form
    {
        public FrmMain()
        {
            InitializeComponent();
        }

        private BindingList<string> shoppingList;

        private void FrmMain_Load(object sender, EventArgs e)
        {           
            //let's just add some items to the list
            string[] items = { "Rice", "Milk", "Asparagus", "Olive Oil", "Tomatoes", "Bread" };
            shoppingList = new BindingList<string>(items.ToList());

            shoppingList.AllowNew = true; //if this is not set error: "Unable to add a row: Row insertion not supported by this data source" is thrown

            ugList.DataSource = shoppingList;
            shoppingList.ListChanged += new ListChangedEventHandler(ShoppingList_ListChanged);
        }

        public void ShoppingList_ListChanged(object sender, ListChangedEventArgs e)
        {
            MessageBox.Show(e.ListChangedType.ToString()); //what happened to the list?
        }

        private void ugList_InitializeLayout(object sender, Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs e)
        {
            e.Layout.Override.CellClickAction = CellClickAction.RowSelect;
            e.Layout.Override.AllowDelete = DefaultableBoolean.True;
            e.Layout.Override.AllowAddNew = AllowAddNew.TemplateOnBottom;
        }

    private void btnAddCookies_Click(object sender, EventArgs e)
    {
        shoppingList.Add("Cookies");
        ugList.Refresh();
    }
}

我尝试添加一个按钮来手动将项目添加到列表中而不涉及UltraWinGrid（btnAddCookies_Click），这没有问题。

有什么想法可以帮助我朝着正确的方向前进？感谢

Answer 1

BindingList<string> AllowNew到true会导致绑定列表通过反射创建新项目。 bindinglist的作用是通过反射实例化generictype（在本例中为string）。这也是导致异常的原因。因为字符串valuetype没有任何构造函数。将自己创建的类型与构造函数绑定肯定是可能的。在这种情况下，您可以创建一个包装类：

    public class MyList
    {
        public string ListItem { get; set; }

        public MyList( string listItem )
        {
            ListItem = listItem;
        }
    }

并绑定此类：BindingList<MyList> bindingList = new BindingList<MyList>();

UltraWinGrid绑定到BindingList <string>，添加行错误</string>

1 个答案: