[英]C# - troubles with sorting datagridview
我已经搜寻了我的屁股来解决我的问题。 我已经开发了带有一些datagridviews的ac#Winforms程序。
问题是我希望成为能够通过单击列标题对datagridview进行排序的用户(我认为这将是标准的……),但是它不起作用。
我尝试了dgv.Sort方法,但这引发了一个例外,即必须将datagridview绑定到IBindingList,但是我不知道如何执行该操作,并且我真的不想重新开发所有内容。
这是我填充dgv的方法。
我有某些自定义对象,并将它们放入列表中。 当此列表完全填充后,我将其设置为dgv的数据源。
list.Add(costumobject);
.
.
.
dgv.DataSource = list;
您能告诉我一种使排序功能起作用的快速方法吗?
亲切的问候,
List<T>
不支持直接排序。
相反,您可以使用Linq例程进行排序。
但是,您将需要包括一个排序字段检查,该检查与列数一样长。
不知道您的customobject
类,让我们尝试使用Name
类:
class Name
{
public string first { get; set; }
public string last { get; set; }
public string middle { get; set; }
public Name (string f, string m, string l)
{
first = f; middle = m; last = l;
}
}
现在,让我们对ColumnHeaderMouseClick
事件进行编码:
private void dataGridView1_ColumnHeaderMouseClick(object sender,
DataGridViewCellMouseEventArgs e)
{
List<Name> names = dataGridView1.DataSource as List<Name>;
string col = dataGridView2.Columns[e.ColumnIndex].DataPropertyName;
string order = " ASC";
if (dataGridView1.Tag != null)
order = dataGridView1.Tag.ToString().Contains(" ASC") ? " DESC" : " ASC";
dataGridView1.Tag = col + order;
if (order.Contains(" ASC"))
names = names.OrderBy(x => col == "first"? x.first
: col == "last" ? x.last : x.middle).ToList();
else
names = names.OrderByDescending(x => col == "first"? x.first :
col == "last" ? x.last : x.middle).ToList();
dataGridView1.DataSource = names;
}
请注意,我将当前的排序列和顺序存储在DGV的Tag
。 您可以将其移动到类级别的变量或其他位置。 不幸的是,无法设置DGV的SortOrder
属性。
创建一个SortableBindingList而不是一个List。
using System;
using System.Collections.Generic;
using System.ComponentModel;
namespace YourNamespace
{
/// <summary>
/// Provides a generic collection that supports data binding and additionally supports sorting.
/// See http://msdn.microsoft.com/en-us/library/ms993236.aspx
/// If the elements are IComparable it uses that; otherwise compares the ToString()
/// </summary>
/// <typeparam name="T">The type of elements in the list.</typeparam>
public class SortableBindingList<T> : BindingList<T> where T : class
{
private bool _isSorted;
private ListSortDirection _sortDirection = ListSortDirection.Ascending;
private PropertyDescriptor _sortProperty;
/// <summary>
/// Initializes a new instance of the <see cref="SortableBindingList{T}"/> class.
/// </summary>
public SortableBindingList()
{
}
/// <summary>
/// Initializes a new instance of the <see cref="SortableBindingList{T}"/> class.
/// </summary>
/// <param name="list">An <see cref="T:System.Collections.Generic.IList`1" /> of items to be contained in the <see cref="T:System.ComponentModel.BindingList`1" />.</param>
public SortableBindingList(IList<T> list) : base(list)
{
}
/// <summary>
/// Gets a value indicating whether the list supports sorting.
/// </summary>
protected override bool SupportsSortingCore
{
get { return true; }
}
/// <summary>
/// Gets a value indicating whether the list is sorted.
/// </summary>
protected override bool IsSortedCore
{
get { return _isSorted; }
}
/// <summary>
/// Gets the direction the list is sorted.
/// </summary>
protected override ListSortDirection SortDirectionCore
{
get { return _sortDirection; }
}
/// <summary>
/// Gets the property descriptor that is used for sorting the list if sorting is implemented in a derived class; otherwise, returns null
/// </summary>
protected override PropertyDescriptor SortPropertyCore
{
get { return _sortProperty; }
}
/// <summary>
/// Removes any sort applied with ApplySortCore if sorting is implemented
/// </summary>
protected override void RemoveSortCore()
{
_sortDirection = ListSortDirection.Ascending;
_sortProperty = null;
_isSorted = false; //thanks Luca
}
/// <summary>
/// Sorts the items if overridden in a derived class
/// </summary>
/// <param name="prop"></param>
/// <param name="direction"></param>
protected override void ApplySortCore(PropertyDescriptor prop, ListSortDirection direction)
{
_sortProperty = prop;
_sortDirection = direction;
List<T> list = Items as List<T>;
if (list == null) return;
list.Sort(Compare);
_isSorted = true;
//fire an event that the list has been changed.
OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
}
private int Compare(T lhs, T rhs)
{
var result = OnComparison(lhs, rhs);
//invert if descending
if (_sortDirection == ListSortDirection.Descending)
result = -result;
return result;
}
private int OnComparison(T lhs, T rhs)
{
object lhsValue = lhs == null ? null : _sortProperty.GetValue(lhs);
object rhsValue = rhs == null ? null : _sortProperty.GetValue(rhs);
if (lhsValue == null)
{
return (rhsValue == null) ? 0 : -1; //nulls are equal
}
if (rhsValue == null)
{
return 1; //first has value, second doesn't
}
if (lhsValue is IComparable)
{
return ((IComparable)lhsValue).CompareTo(rhsValue);
}
if (lhsValue.Equals(rhsValue))
{
return 0; //both are the same
}
//not comparable, compare ToString
return lhsValue.ToString().CompareTo(rhsValue.ToString());
}
}
}
更改数据源后您是否尝试过刷新数据网格?
list.Add(costumobject);
.
.
.
dgv.DataSource = list;
dgv.Refresh();
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