带有DataGrid的WPF应用程序中的C#搜索框

嗨，我在网站上搜索了一下，没有找到我的问题的答案。我读到了这个：http://davidowens.wordpress.com/2009/02/18/wpf-search-text-box/这是从另一个关于wpf搜索框的问题中提出的。我有一个C#WPF应用程序，我正在使用Access DB。在我的数据输入屏幕上，我有一个搜索框和一个显示数据库中所有记录的数据网格。我目前的搜索是有效的，但不是我想象的那样。我希望用户能够开始在搜索框中键入，数据网格中显示的记录列表将开始根据他们键入的内容进行筛选。我写的代码本以为会这样做，但为了让他们进行搜索，他们必须键入：people*，然后点击回车键，它就会显示结果。我想知道有没有一种方法可以修改我的代码，使其不需要星号，并在键入时进行筛选，或者应该以不同的方式编写？我的数据输入xaml页面文本框名称如下：

<TextBox x:Name="txtSearch" Grid.Column="1" FontSize="14" Margin="10, 0, 10, 0" Text="{Binding Path=SearchString,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

在下面的datahelper.cs上：

    private void Search(string inputSearchString)
    {
        inputSearchString = inputSearchString.ToLower();
        LastSearchTerm = inputSearchString;
        FilteredCaseCollection.Clear();
        if (String.IsNullOrEmpty(inputSearchString.Trim()))
        {
            foreach (CaseViewModel caseVM in CaseCollection)
            {
                FilteredCaseCollection.Add(caseVM);
            }
        }
        else
        {
            inputSearchString = inputSearchString.Replace(" =", "=").Replace("= ", "=").Replace(" = ", "=");
            string[] termsArray = inputSearchString.Split(' ');
            int count = 0;
            foreach (CaseViewModel caseVM in CaseCollection)
            {
                count++;
                Type t = caseVM.GetType();
                foreach (PropertyInfo propertyInfo in t.GetProperties())
                {
                    if (propertyInfo.CanRead)
                    {
                        object value = propertyInfo.GetValue(caseVM, null);
                        if (value == null)
                        {
                            value = String.Empty;
                        }
                        string name = propertyInfo.Name.ToLower();
                        foreach (string term in termsArray)
                        {
                            if (term.ToLower().Equals(value.ToString().ToLower()))
                            {
                                if (!FilteredCaseCollection.Contains(caseVM))
                                {
                                    FilteredCaseCollection.Add(caseVM);
                                }
                            }
                            else if (term.ToLower().Contains("*") && MatchWildcardString(term.ToLower(), value.ToString().ToLower()))
                            {
                                if (!FilteredCaseCollection.Contains(caseVM))
                                {
                                    FilteredCaseCollection.Add(caseVM);
                                }
                            }
                        }
                    }
                }
            }
        }
    }
    public bool MatchWildcardString(string pattern, string input)
    {
        if (String.Compare(pattern, input) == 0)
        {
            return true;
        }
        else if (String.IsNullOrEmpty(input))
        {
            if (String.IsNullOrEmpty(pattern.Trim(new Char[1] { '*' })))
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        else if (pattern.Length == 0)
        {
            return false;
        }
        else if (pattern[0] == '?')
        {
            return MatchWildcardString(pattern.Substring(1), input.Substring(1));
        }
        else if (pattern[pattern.Length - 1] == '?')
        {
            return MatchWildcardString(pattern.Substring(0, pattern.Length - 1), input.Substring(0, input.Length - 1));
        }
        else if (pattern[0] == '*')
        {
            if (MatchWildcardString(pattern.Substring(1), input))
            {
                return true;
            }
            else
            {
                return MatchWildcardString(pattern, input.Substring(1));
            }
        }
        else if (pattern[pattern.Length - 1] == '*')
        {
            if (MatchWildcardString(pattern.Substring(0, pattern.Length - 1), input))
            {
                return true;
            }
            else
            {
                return MatchWildcardString(pattern, input.Substring(0, input.Length - 1));
            }
        }
        else if (pattern[0] == input[0])
        {
            return MatchWildcardString(pattern.Substring(1), input.Substring(1));
        }
        return false;
    }

<Grid x:Name="LayoutRoot">
    <Grid.RowDefinitions>
        <RowDefinition/>
        <RowDefinition/>
    </Grid.RowDefinitions>
    <TextBox x:Name="txtSearch" Grid.Row="0" FontSize="14" Margin="10, 0, 10, 0" Height="28" Width="74"
             Text="{Binding Path=SearchString, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
    <DataGrid Grid.Row="1" AutoGenerateColumns="True" ItemsSource="{Binding FilteredClients, Mode=TwoWay}" SelectedItem="{Binding SelectedClient}" />
</Grid>
    public class MainViewModel : ViewModelBase
{
    public MainViewModel(IDataService dataService)
    {
        allClients = new List<Client>();
        filteredClients = new List<Client>();
        GetAll();
    }

    public const string SearchStringPropertyName = "SearchString";
    private string searchString = string.Empty;
    public string SearchString
    {
        get
        {
            return searchString;
        }
        set
        {
            if (searchString == value)
            {
                return;
            }
            searchString = value;
            if (searchString == string.Empty)
            {
                filteredClients = allClients;
            }
            else
            {
                FilterAll();
            }
            RaisePropertyChanged(FilteredClientsPropertyName);
            RaisePropertyChanged(SearchStringPropertyName);
        }
    }
    public const string AllClientsPropertyName = "AllClients";
    private List<Client> allClients;
    public List<Client> AllClients
    {
        get
        {
            return allClients;
        }
        set
        {
            if (allClients == value)
            {
                return;
            }
            RaisePropertyChanging(AllClientsPropertyName);
            allClients = value;
            RaisePropertyChanged(AllClientsPropertyName);
        }
    }
    public const string FilteredClientsPropertyName = "FilteredClients";
    private List<Client> filteredClients;
    public List<Client> FilteredClients
    {
        get
        {
            return filteredClients;
        }
        set
        {
            if (filteredClients == value)
            {
                return;
            }
            RaisePropertyChanging(FilteredClientsPropertyName);
            filteredClients = value;
            RaisePropertyChanged(FilteredClientsPropertyName);
        }
    }
    public const string SelectedClientPropertyName = "SelectedClient";
    private Client selectedClient;
    public Client SelectedClient
    {
        get
        {
            return selectedClient;
        }
        set
        {
            if (selectedClient == value)
            {
                return;
            }
            RaisePropertyChanging(SelectedClientPropertyName);
            selectedClient = value;
            RaisePropertyChanged(SelectedClientPropertyName);
        }
    }
    private void GetAll()
    {
        AddClient("sally", "may", 10000);
        AddClient("bert", "benning", 10000);
        AddClient("ernie", "manning", 10000);
        AddClient("lisa", "ann", 10000);
        AddClient("michael", "douglas", 10000);
        AddClient("charlie", "sheen", 10000);
        filteredClients = allClients;
    }
    private void AddClient(String firstname, String lastname, Double salary)
    {
        Client clientadd = new Client();
        clientadd.FirstName = firstname;
        clientadd.LastName = lastname;
        clientadd.Salary = salary;
        allClients.Add(clientadd);
    }
    private void FilterAll()
    {
        filteredClients = (from c in allClients where c.FullName.Contains(searchString) orderby c.FullName select c).ToList();
    }
}
public class Client
{
    public String FirstName { get; set; }
    public String LastName { get; set; }
    public Double Salary { get; set; }
    public String FullName { get { return LastName + ", " + FirstName; } }
    public List<Client> Clients { get; set; }
}

if (term.ToLower().Equals(value.ToString().ToLower()))

if (value.ToString().ToLower().StartsWith(term.ToLower())

if (value.ToString().ToLower().Contains(term.ToLower())