wpf下ComboBox自动过滤下拉内容，在xaml中使用下面这个类就可以了

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.ComponentModel;

using System.Windows.Data;

using System.Windows.Controls;

using System.Windows;

using System.Globalization;

namespace YouNameSpace

{

class AutoFilteredComboBox : ComboBox

{

private int silenceEvents = 0;

/// <summary>

/// Creates a new instance of <see cref="AutoFilteredComboBox" />.

/// </summary>

public AutoFilteredComboBox()

{

DependencyPropertyDescriptor textProperty = DependencyPropertyDescriptor.FromProperty(

ComboBox.TextProperty, typeof(AutoFilteredComboBox));

textProperty.AddValueChanged(this, this.OnTextChanged);

this.RegisterIsCaseSensitiveChangeNotification();

this.IsEditable = true;

}

#region IsCaseSensitive Dependency Property

/// <summary>

/// The <see cref="DependencyProperty"/> object of the <see cref="IsCaseSensitive" /> dependency property.

/// </summary>

public static readonly DependencyProperty IsCaseSensitiveProperty =

DependencyProperty.Register("IsCaseSensitive", typeof(bool), typeof(AutoFilteredComboBox), new UIPropertyMetadata(false));

/// <summary>

/// Gets or sets the way the combo box treats the case sensitivity of typed text.

/// </summary>

/// <value>The way the combo box treats the case sensitivity of typed text.</value>

[System.ComponentModel.Description("The way the combo box treats the case sensitivity of typed text.")]

[System.ComponentModel.Category("AutoFiltered ComboBox")]

[System.ComponentModel.DefaultValue(true)]

public bool IsCaseSensitive

{

[System.Diagnostics.DebuggerStepThrough]

get

{

return (bool)this.GetValue(IsCaseSensitiveProperty);

}

[System.Diagnostics.DebuggerStepThrough]

set

{

this.SetValue(IsCaseSensitiveProperty, value);

}

}

protected virtual void OnIsCaseSensitiveChanged(object sender, EventArgs e)

{

if (this.IsCaseSensitive)

this.IsTextSearchEnabled = false;

this.RefreshFilter();

}

private void RegisterIsCaseSensitiveChangeNotification()

{

System.ComponentModel.DependencyPropertyDescriptor.FromProperty(IsCaseSensitiveProperty, typeof(AutoFilteredComboBox)).AddValueChanged(

this, this.OnIsCaseSensitiveChanged);

}

#endregion

#region DropDownOnFocus Dependency Property

/// <summary>

/// The <see cref="DependencyProperty"/> object of the <see cref="DropDownOnFocus" /> dependency property.

/// </summary>

public static readonly DependencyProperty DropDownOnFocusProperty =

DependencyProperty.Register("DropDownOnFocus", typeof(bool), typeof(AutoFilteredComboBox), new UIPropertyMetadata(true));

/// <summary>

/// Gets or sets the way the combo box behaves when it receives focus.

/// </summary>

/// <value>The way the combo box behaves when it receives focus.</value>

[System.ComponentModel.Description("The way the combo box behaves when it receives focus.")]

[System.ComponentModel.Category("AutoFiltered ComboBox")]

[System.ComponentModel.DefaultValue(true)]

public bool DropDownOnFocus

{

[System.Diagnostics.DebuggerStepThrough]

get

{

return (bool)this.GetValue(DropDownOnFocusProperty);

}

[System.Diagnostics.DebuggerStepThrough]

set

{

this.SetValue(DropDownOnFocusProperty, value);

}

}

#endregion

#region | Handle selection |

/// <summary>

/// Called when <see cref="ComboBox.ApplyTemplate()"/> is called.

/// </summary>

public override void OnApplyTemplate()

{

base.OnApplyTemplate();

this.EditableTextBox.SelectionChanged += this.EditableTextBox_SelectionChanged;

}

/// <summary>

/// Gets the text box in charge of the editable portion of the combo box.

/// </summary>

protected TextBox EditableTextBox

{

get

{

TextBox TxtBox = (TextBox)this.Template.FindName("PART_EditableTextBox", this);

return TxtBox;

}

}

private int start = 0, length = 0;

private void EditableTextBox_SelectionChanged(object sender, RoutedEventArgs e)

{

if (this.silenceEvents == 0)

{

this.start = ((TextBox)(e.OriginalSource)).SelectionStart;

this.length = ((TextBox)(e.OriginalSource)).SelectionLength;

this.RefreshFilter();

}

}

#endregion

#region | Handle focus |

/// <summary>

/// Invoked whenever an unhandled <see cref="UIElement.GotFocus" /> event

/// reaches this element in its route.

/// </summary>

/// <param name="e">The <see cref="RoutedEventArgs" /> that contains the event data.</param>

protected override void OnGotFocus(RoutedEventArgs e)

{

base.OnGotFocus(e);

if (this.ItemsSource != null && this.DropDownOnFocus)

{

this.IsDropDownOpen = true;

}

}

#endregion

#region | Handle filtering |

private void RefreshFilter()

{

if (this.ItemsSource != null)

{

ICollectionView view = CollectionViewSource.GetDefaultView(this.ItemsSource);

view.Refresh();

this.IsDropDownOpen = true;

}

}

private bool FilterPredicate(object value)

{

// We don't like nulls.

if (value == null)

return false;

// If there is no text, there's no reason to filter.

if (this.Text.Length == 0)

return true;

string prefix = this.Text;

// If the end of the text is selected, do not mind it.

if (this.length > 0 && this.start + this.length == this.Text.Length)

{

prefix = prefix.Substring(0, this.start);

}

//return value.ToString()

// .StartsWith(prefix, !this.IsCaseSensitive, CultureInfo.CurrentCulture);

return value.ToString()

.Contains(prefix);

}

#endregion

/// <summary>

/// Called when the source of an item in a selector changes.

/// </summary>

/// <param name="oldValue">Old value of the source.</param>

/// <param name="newValue">New value of the source.</param>

protected override void OnItemsSourceChanged(System.Collections.IEnumerable oldValue, System.Collections.IEnumerable newValue)

{

if (newValue != null)

{

ICollectionView view = CollectionViewSource.GetDefaultView(newValue);

view.Filter += this.FilterPredicate;

}

if (oldValue != null)

{

ICollectionView view = CollectionViewSource.GetDefaultView(oldValue);

view.Filter -= this.FilterPredicate;

}

base.OnItemsSourceChanged(oldValue, newValue);

}

private void OnTextChanged(object sender, EventArgs e)

{

if (!this.IsTextSearchEnabled && this.silenceEvents == 0)

{

this.RefreshFilter();

// Manually simulate the automatic selection that would have been

// available if the IsTextSearchEnabled dependency property was set.

if (this.Text.Length > 0)

{

foreach (object item in CollectionViewSource.GetDefaultView(this.ItemsSource))

{

int text = item.ToString().Length, prefix = this.Text.Length;

this.SelectedItem = item;

this.silenceEvents++;

this.EditableTextBox.Text = item.ToString();

this.EditableTextBox.Select(prefix, text - prefix);

this.silenceEvents--;

break;

}

}

}

}

}

}