BindingSource.Filter 屬性

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

來源:

BindingSource.cs

取得或設定用來篩選顯示列的表達式。

public:
 virtual property System::String ^ Filter { System::String ^ get(); void set(System::String ^ value); };

public virtual string? Filter { get; [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members of types used in the filter expression might be trimmed.")] set; }

[<set: System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members of types used in the filter expression might be trimmed.")>]
member this.Filter : string with get, set

Public Overridable Property Filter As String

屬性值

String

一個字串，指定列如何被過濾。 預設值為 null。

實作

Filter

屬性

RequiresUnreferencedCodeAttribute

範例

以下範例說明如何使用 該Filter性質。DataView 執行此範例時，將程式碼貼上到 Windows 表單，並呼叫 PopulateDataViewAndFilter 表單的建構子或 Load 事件處理方法。 你的表單應該會匯入 System.Xml 和 System.IO 命名空間。

private void PopulateDataViewAndFilter()
{
    DataSet set1 = new DataSet();

    // Some xml data to populate the DataSet with.
    string musicXml =
        "<?xml version='1.0' encoding='UTF-8'?>" +
        "<music>" +
        "<recording><artist>Coldplay</artist><cd>X&Y</cd></recording>" +
        "<recording><artist>Dave Matthews</artist><cd>Under the Table and Dreaming</cd></recording>" +
        "<recording><artist>Dave Matthews</artist><cd>Live at Red Rocks</cd></recording>" +
        "<recording><artist>Natalie Merchant</artist><cd>Tigerlily</cd></recording>" +
        "<recording><artist>U2</artist><cd>How to Dismantle an Atomic Bomb</cd></recording>" +
        "</music>";

    // Read the xml.
    StringReader reader = new StringReader(musicXml);
    set1.ReadXml(reader);

    // Get a DataView of the table contained in the dataset.
    DataTableCollection tables = set1.Tables;
    DataView view1 = new DataView(tables[0]);

    // Create a DataGridView control and add it to the form.
    DataGridView datagridview1 = new DataGridView();
    datagridview1.AutoGenerateColumns = true;
    this.Controls.Add(datagridview1);

    // Create a BindingSource and set its DataSource property to
    // the DataView.
    BindingSource source1 = new BindingSource();
    source1.DataSource = view1;

    // Set the data source for the DataGridView.
    datagridview1.DataSource = source1;

    //The Filter string can include Boolean expressions.
    source1.Filter = "artist = 'Dave Matthews' OR cd = 'Tigerlily'";
}

Private Sub PopulateDataViewAndFilter() 
    Dim set1 As New DataSet()
    
    ' Some xml data to populate the DataSet with.
    Dim musicXml As String = "<?xml version='1.0' encoding='UTF-8'?>" & _
        "<music>" & _
        "<recording><artist>Coldplay</artist><cd>X&Y</cd></recording>" & _
        "<recording><artist>Dave Matthews</artist><cd>Under the Table and Dreaming</cd></recording>" & _
        "<recording><artist>Dave Matthews</artist><cd>Live at Red Rocks</cd></recording>" & _
        "<recording><artist>Natalie Merchant</artist><cd>Tigerlily</cd></recording>" & _
        "<recording><artist>U2</artist><cd>How to Dismantle an Atomic Bomb</cd></recording>" & _
        "</music>"
    
    ' Read the xml.
    Dim reader As New StringReader(musicXml)
    set1.ReadXml(reader)
    
    ' Get a DataView of the table contained in the dataset.
    Dim tables As DataTableCollection = set1.Tables
    Dim view1 As New DataView(tables(0))
    
    ' Create a DataGridView control and add it to the form.
    Dim datagridview1 As New DataGridView()
    datagridview1.AutoGenerateColumns = True
    Me.Controls.Add(datagridview1)
    
    ' Create a BindingSource and set its DataSource property to
    ' the DataView.
    Dim source1 As New BindingSource()
    source1.DataSource = view1
    
    ' Set the data source for the DataGridView.
    datagridview1.DataSource = source1
    
    ' The Filter string can include Boolean expressions.
    source1.Filter = "artist = 'Dave Matthews' OR cd = 'Tigerlily'"

End Sub

備註

通常用於複雜的資料綁定情境，該 Filter 屬性允許您查看 的 DataSource子集。 只有實作該 IBindingListView 介面的底層清單支援過濾。

當 Filter 不是 null時，會 BindingSource 將此性質傳遞給底層清單。 如果你在物件初始化時設定此屬性，呼叫會延後直到初始化完成後。

要形成濾波器值，先指定欄位名稱，後接運算子和一個篩選用的值。 被接受的過濾語法取決於底層資料來源。 如果底層資料來源是 DataSet、 DataTable或 DataView，你可以使用該屬性所記錄 DataColumn.Expression 的語法來指定布林運算式。

房產的 Filter 價值會影響房產 Count 本身的價值。 此外，當資料來源變更時，該 Filter 值仍會持續存在。 要停止過濾 ， DataSource呼叫 方法 RemoveFilter 。

另請參閱

• DataSource
• List
• Sort
• RemoveFilter()
• IsSorted