C# · 12月 25, 2021

c# – DataGridView使用SortableBindingList

我有一个函数返回一个IList< T>并且是DataGridView的DataSource.我了解到DataGridView不会对IList进行排序.我读了 This stackoverflow Q&A,我试图实现SortableBindingList.我必须做错事,因为我的DataGridView是空的.我也试图从一个Text@R_577_2419@的SortableBindingSource访问一个元素,也没有. using Microsoft.sqlServer.Management.Controls;public partial class Form1 : Form{ IBusinessLayer businessLayer; IList<Category> categories; SortableBindingList<Category> catSortable; public Form1() { InitializeComponent(); } private void Form1_Load(object sender,EventArgs e) { businessLayer = new BusinessLayer(); categories = businessLayer.GetAllCategories(); catSortable = new SortableBindingList<Category>(categories); categoryBindingSource.DataSource = catSortable; categoryDataGridView.DataSource = categoryBindingSource; text@R_577_2419@1.Text = catSortable[0].CategoryName; }}

我检查了Microsoft.sqlServer.Management.Controls,这样看起来不错吗?

namespace Microsoft.sqlServer.Management.Controls{ public class SortableBindingList<T> : BindingList<T> { public SortableBindingList(); public SortableBindingList(IList<T> list); protected override bool IsSortedCore { get; } protected override ListSortDirection SortDirectionCore { get; } protected override PropertyDescriptor SortPropertyCore { get; } protected override bool SupportsSortingCore { get; } protected override void ApplySortCore(PropertyDescriptor prop,ListSortDirection direction); protected override void RemoveSortCore(); }}

我非常感谢帮助,帮助我学习.感谢大家!

解决方法 尝试这个SortableBindingList: public class SortableBindingList<T> : BindingList<T>{ private bool isSortedValue; ListSortDirection sortDirectionValue; PropertyDescriptor sortPropertyValue; public SortableBindingList() { } public SortableBindingList(IList<T> list) { foreach (object o in list) { this.Add((T)o); } } protected override void ApplySortCore(PropertyDescriptor prop,ListSortDirection direction) { Type interfaceType = prop.PropertyType.GetInterface(“IComparable”); if (interfaceType == null && prop.PropertyType.IsValueType) { Type underlyingType = Nullable.GetUnderlyingType(prop.PropertyType); if (underlyingType != null) { interfaceType = underlyingType.GetInterface(“IComparable”); } } if (interfaceType != null) { sortPropertyValue = prop; sortDirectionValue = direction; IEnumerable<T> query = base.Items; if (direction == ListSortDirection.Ascending) { query = query.OrderBy(i => prop.GetValue(i)); } else { query = query.OrderByDescending(i => prop.GetValue(i)); } int newIndex = 0; foreach (object item in query) { this.Items[newIndex] = (T)item; newIndex++; } isSortedValue = true; this.OnListChanged(new ListChangedEventArgs(ListChangedType.Reset,-1)); } else { throw new NotSupportedException(“Cannot sort by ” + prop.Name + “. This” + prop.PropertyType.ToString() + ” does not implement IComparable”); } } protected override PropertyDescriptor SortPropertyCore { get { return sortPropertyValue; } } protected override ListSortDirection SortDirectionCore { get { return sortDirectionValue; } } protected override bool SupportsSortingCore { get { return true; } } protected override bool IsSortedCore { get { return isSortedValue; } }}