DataView.RowFilter DataView.RowFilter DataView.RowFilter DataView.RowFilter Property

Définition

Obtient ou définit l’expression utilisée pour filtrer les lignes qui s’affichent dans DataView.Gets or sets the expression used to filter which rows are viewed in the DataView.

public:
 virtual property System::String ^ RowFilter { System::String ^ get(); void set(System::String ^ value); };
[System.Data.DataSysDescription("DataViewRowFilterDescr")]
public virtual string RowFilter { get; set; }
member this.RowFilter : string with get, set
Public Overridable Property RowFilter As String

Valeur de propriété

Chaîne qui spécifie la manière dont les lignes sont filtrées.A string that specifies how rows are to be filtered.

Exemples

L’exemple suivant crée un DataView et définit ses RowFilter propriété.The following example creates a DataView and sets its RowFilter property.

using System;
using System.Data;
using System.Windows.Forms;

public class Form1 : Form {
   protected TextBox Text1;
   protected DataSet DataSet1;

   public static void Main() {
      DemostrateDataView();
   }

   private static void DemostrateDataView() {
      // Create a DataTable with one column
      DataTable dt = new DataTable("MyTable");
      DataColumn column = new DataColumn("Col", typeof(int));
      dt.Columns.Add(column); 

      // Add 5 rows on Added state
      for (int i = 0; i < 5; i++) {
         DataRow row = dt.NewRow();
         row["Col"] = i;
         dt.Rows.Add(row);
      }

      // Add 5 rows on Unchanged state
      for (int i = 5; i < 10; i++) {
         DataRow row = dt.NewRow();
         row["Col"] = i;
         dt.Rows.Add(row);
         // Calling AcceptChanges will make the DataRowVersion change from Added to Unchanged in this case
         row.AcceptChanges();
      }

      // Create a DataView
      DataView dv = new DataView(dt);

      Console.WriteLine("Print unsorted, unfiltered DataView");
      PrintDataView(dv);

      // Changing the Sort order to descending
      dv.Sort = "Col DESC";

      Console.WriteLine("Print sorted DataView. Sort = 'Col DESC'");
      PrintDataView(dv);

      // Filter by an expression. Filter all rows where column 'Col' have values greater or equal than 3
      dv.RowFilter = "Col < 3";

      Console.WriteLine("Print sorted and Filtered DataView by RowFilter. RowFilter = 'Col > 3'");
      PrintDataView(dv);

      // Removing Sort and RpwFilter to ilustrate RowStateFilter. DataView should contain all 10 rows back in the original order
      dv.Sort = String.Empty;
      dv.RowFilter = String.Empty;

      // Show only Unchanged rows or last 5 rows
      dv.RowStateFilter = DataViewRowState.Unchanged;

      Console.WriteLine("Print Filtered DataView by RowState. RowStateFilter =  DataViewRowState.Unchanged");
      PrintDataView(dv);
   }

   private static void PrintDataView(DataView dv) {
      // Printing first DataRowView to demo that the row in the first index of the DataView changes depending on sort and filters
      Console.WriteLine("First DataRowView value is '{0}'", dv[0]["Col"]);

      // Printing all DataRowViews
      foreach (DataRowView drv in dv) {
         Console.WriteLine("\t {0}", drv["Col"]);
      }
   }
}
Imports System
Imports System.Data
Imports System.Windows.Forms

Public Class Form1
    Inherits Form
    Protected Text1 As TextBox
    Protected DataSet1 As DataSet

    Public Shared Sub Main()
        DemostrateDataView()
    End Sub

    Private Shared Sub DemostrateDataView()
        ' Create a DataTable with one column
        Dim dt As New DataTable("MyTable")
        Dim column As New DataColumn("Col", GetType(Integer))
        dt.Columns.Add(column)

        ' Add 5 rows on Added state
        For i As Integer = 0 To 4
            Dim row As DataRow = dt.NewRow()
            row("Col") = i
            dt.Rows.Add(row)
        Next

        ' Add 5 rows on Unchanged state
        For i As Integer = 5 To 9
            Dim row As DataRow = dt.NewRow()
            row("Col") = i
            dt.Rows.Add(row)
            ' Calling AcceptChanges will make the DataRowVersion change from Added to Unchanged in this case
            row.AcceptChanges()
        Next

        ' Create a DataView
        Dim dv As New DataView(dt)

        Console.WriteLine("Print unsorted, unfiltered DataView")
        PrintDataView(dv)

        ' Changing the Sort order to descending
        dv.Sort = "Col DESC"

        Console.WriteLine("Print sorted DataView. Sort = 'Col DESC'")
        PrintDataView(dv)

        ' Filter by an expression. Filter all rows where column 'Col' have values greater or equal than 3
        dv.RowFilter = "Col < 3"

        Console.WriteLine("Print sorted and Filtered DataView by RowFilter. RowFilter = 'Col > 3'")
        PrintDataView(dv)

        ' Removing Sort and RpwFilter to ilustrate RowStateFilter. DataView should contain all 10 rows back in the original order
        dv.Sort = [String].Empty
        dv.RowFilter = [String].Empty

        ' Show only Unchanged rows or last 5 rows
        dv.RowStateFilter = DataViewRowState.Unchanged

        Console.WriteLine("Print Filtered DataView by RowState. RowStateFilter =  DataViewRowState.Unchanged")
        PrintDataView(dv)
    End Sub

    Private Shared Sub PrintDataView(dv As DataView)
        ' Printing first DataRowView to demo that the row in the first index of the DataView changes depending on sort and filters
        Console.WriteLine("First DataRowView value is '{0}'", dv(0)("Col"))

        ' Printing all DataRowViews
        For Each drv As DataRowView In dv
            Console.WriteLine(vbTab & " {0}", drv("Col"))
        Next
    End Sub
End Class

Remarques

Pour former un RowFilter valeur, spécifiez le nom d’une colonne suivie d’un opérateur et une valeur sur laquelle filtrer.To form a RowFilter value, specify the name of a column followed by an operator and a value to filter on. La valeur doit être entre guillemets.The value must be in quotation marks. Par exemple :For example:

"LastName = 'Smith'""LastName = 'Smith'"

Consultez le Expression propriété de la DataColumn classe pour plus d’informations.See the Expression property of the DataColumn class for more information.

Pour retourner uniquement les colonnes avec des valeurs null, utilisez l’expression suivante :To return only those columns with null values, use the following expression:

"Isnull(Col1,'Null Column') = 'Null Column'""Isnull(Col1,'Null Column') = 'Null Column'"

S’applique à

Voir aussi