使用 Telerik RadGridView 进行不区分大小写和变音符号的过滤

Question

标题几乎说明了一切。如何使用 Telerik RadGridView 进行不区分大小写和不区分变音标记的过滤？

我在 Google 上找到了许多可行的解决方案，但没有一个是简单易用的，此外，在许多情况下，它改变了 RadGridView 的 UI 行为，使其对最终用户的吸引力降低。

Answer 1

多年来，我的经验和技能不断增长，所以我终于想出了一个简单易用的解决方案。它适用于 WinForms 2017 R1 或更高版本以及 Visual Studio 2015 或更高版本的 Telerik UI。

这里是帮助类，RadGridViewHelper：

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Globalization;
using System.Linq;
using Telerik.WinControls.Data;
using Telerik.WinControls.UI;

namespace MySoftware.Helpers
{
    internal static class RadGridViewHelper
    {
        private class CustomStringFilteringClass
        {
            private RadGridView RadGridView { get; }
            private bool _enabled;
            private ReadOnlyCollection<string> StringColumns { get; }

            public CustomStringFilteringClass(RadGridView radGridView)
            {
                RadGridView = radGridView;
                StringColumns = new ReadOnlyCollection<string>(GetStringColumns(radGridView));
            }

            public void Enable()
            {
                if (_enabled) throw new InvalidOperationException("Can't call this method twice");
                _enabled = true;

                RadGridView.EnableCustomFiltering = true;
                RadGridView.CustomFiltering += RadGridViewOnCustomFiltering;
            }

            private void RadGridViewOnCustomFiltering(object sender, GridViewCustomFilteringEventArgs e)
            {
                if (RadGridView.FilterDescriptors.Count == 0) return;

                var row = e.Row;

                foreach (var stringColumn in StringColumns)
                {
                    var filterDescriptors = RadGridView.FilterDescriptors.Where(
                        x => x.PropertyName == stringColumn).ToList();
                    if (filterDescriptors.Count != 1)
                    {
                        continue;
                    }
                    var filterDescriptor = filterDescriptors.First();
                    var cellValue = ((string) row.Cells[stringColumn].Value).ToLowerInvariant();
                    if (filterDescriptor.GetType() == typeof(CompositeFilterDescriptor))
                    {
                        if (!CompositeFilterEvaluateString((CompositeFilterDescriptor) filterDescriptor, cellValue,
                            RadGridView.MasterTemplate.DataView.FilterEvaluate, row))
                        {
                            e.Visible = false;
                            return;
                        }
                    }
                    else if (!FilterEvaluateString(filterDescriptor, cellValue,
                        RadGridView.MasterTemplate.DataView.FilterEvaluate, row))
                    {
                        e.Visible = false;
                        return;
                    }
                }

                var nonStringFilterDescriptors = RadGridView.FilterDescriptors.Where(
                    x => !StringColumns.Contains(x.PropertyName));
                foreach (var filterDescriptor in nonStringFilterDescriptors)
                {
                    if (!RadGridView.MasterTemplate.DataView.FilterEvaluate(filterDescriptor, row))
                    {
                        e.Visible = false;
                        return;
                    }
                }
            }

            private static bool CompositeFilterEvaluateString(CompositeFilterDescriptor compositeFilterDescriptor,
                string cellValue, Func<FilterDescriptor, GridViewRowInfo, bool> gridFilterEvaluate, GridViewRowInfo row)
            {
                switch (compositeFilterDescriptor.LogicalOperator)
                {
                    case FilterLogicalOperator.And:
                        if (compositeFilterDescriptor.FilterDescriptors.Any(filterDescriptor =>
                        {
                            if (filterDescriptor.GetType() == typeof(CompositeFilterDescriptor))
                                return !CompositeFilterEvaluateString((CompositeFilterDescriptor) filterDescriptor,
                                    cellValue, gridFilterEvaluate, row);
                            return !FilterEvaluateString(filterDescriptor, cellValue, gridFilterEvaluate, row);
                        }))
                            return false;
                        break;
                    case FilterLogicalOperator.Or:
                        if (compositeFilterDescriptor.FilterDescriptors.All(filterDescriptor =>
                        {
                            if (filterDescriptor.GetType() == typeof(CompositeFilterDescriptor))
                                return !CompositeFilterEvaluateString((CompositeFilterDescriptor) filterDescriptor,
                                    cellValue, gridFilterEvaluate, row);
                            return !FilterEvaluateString(filterDescriptor, cellValue, gridFilterEvaluate, row);
                        }))
                            return false;
                        break;
                }
                return true;
            }

            private static bool FilterEvaluateString(FilterDescriptor filterDescriptor, string cellValue,
                Func<FilterDescriptor, GridViewRowInfo, bool> gridFilterEvaluate, GridViewRowInfo row)
            {
                var filterDescriptorValue = ((string) filterDescriptor.Value).ToLowerInvariant();
                switch (filterDescriptor.Operator)
                {
                    case FilterOperator.Contains:
                        if (CultureInfo.InvariantCulture.CompareInfo.IndexOf(cellValue, filterDescriptorValue,
                                CompareOptions.IgnoreNonSpace) == -1)
                            return false;
                        break;
                    case FilterOperator.NotContains:
                        if (CultureInfo.InvariantCulture.CompareInfo.IndexOf(cellValue, filterDescriptorValue,
                                CompareOptions.IgnoreNonSpace) != -1)
                            return false;
                        break;
                    case FilterOperator.StartsWith:
                        if (!CultureInfo.InvariantCulture.CompareInfo.IsPrefix(cellValue, filterDescriptorValue,
                            CompareOptions.IgnoreNonSpace))
                            return false;
                        break;
                    case FilterOperator.EndsWith:
                        if (!CultureInfo.InvariantCulture.CompareInfo.IsSuffix(cellValue, filterDescriptorValue,
                            CompareOptions.IgnoreNonSpace))
                            return false;
                        break;
                    case FilterOperator.IsEqualTo:
                        if (String.Compare(cellValue, filterDescriptorValue, CultureInfo.InvariantCulture,
                                CompareOptions.IgnoreNonSpace) != 0)
                            return false;
                        break;
                    case FilterOperator.IsNotEqualTo:
                        if (String.Compare(cellValue, filterDescriptorValue, CultureInfo.InvariantCulture,
                                CompareOptions.IgnoreNonSpace) == 0)
                            return false;
                        break;
                    default:
                        if (!gridFilterEvaluate.Invoke(filterDescriptor, row))
                            return false;
                        break;
                }
                return true;
            }
        }

        private static List<string> GetStringColumns(RadGridView radGridView)
        {
            var retVal = new List<string>();
            foreach (var column in radGridView.Columns)
            {
                if (column.DataType == typeof(string))
                {
                    retVal.Add(column.Name);
                }
            }
            return retVal;
        }

        /// <summary>
        /// Enables custom string filtering on <paramref name="radGridView"/>. It is case insensitive and
        /// tolerates differences in diacritical marks. For example, in a "equals" comparision, the value
        /// 'ëMúa' is treated as its equal to 'EmÜâ'.
        /// </summary>
        /// <param name="radGridView">Instance of <see cref="RadGridView"/> in which custom string filtering
        /// will be enabled.</param>
        public static void CustomStringFiltering(RadGridView radGridView)
        {
            var customFiltering = new CustomStringFilteringClass(radGridView);
            customFiltering.Enable();
        }
    }
}

用法很简单：

RadGridViewHelper.CustomStringFiltering(radGridView);

其中radGridView 是类RadGridView 的实例，字符串过滤行为将更改为该类。

我在这里以问答的方式提出这个问题，因为这里鼓励：It’s OK to Ask and Answer Your Own Questions - Stack Overflow Blog

希望它对某人有所帮助并节省时间和头痛。