DataTable.Select Método

Definição

Obtém uma matriz de objetos DataRow.Gets an array of DataRow objects.

Sobrecargas

Select()

Obtém uma matriz de todos os objetos DataRow.Gets an array of all DataRow objects.

Select(String)

Obtém uma matriz de todos os objetos DataRow que correspondem aos critérios de filtro.Gets an array of all DataRow objects that match the filter criteria.

Select(String, String)

Obtém uma matriz de todos os objetos DataRow que correspondem aos critérios de filtro, na ordem de classificação especificada.Gets an array of all DataRow objects that match the filter criteria, in the specified sort order.

Select(String, String, DataViewRowState)

Obtém uma matriz de todos os objetos DataRow que correspondem ao filtro, na ordem de classificação correspondente ao estado especificado.Gets an array of all DataRow objects that match the filter in the order of the sort that match the specified state.

Select()

Obtém uma matriz de todos os objetos DataRow.Gets an array of all DataRow objects.

public:
 cli::array <System::Data::DataRow ^> ^ Select();
public System.Data.DataRow[] Select ();
member this.Select : unit -> System.Data.DataRow[]
Public Function Select () As DataRow()

Retornos

Uma matriz de objetos de DataRow.An array of DataRow objects.

Exemplos

O exemplo a seguir retorna uma matriz de objetos DataRow por meio do método Select.The following example returns an array of DataRow objects through the Select method.

private void GetRows()
{
    // Get the DataTable of a DataSet.
    DataTable table = DataSet1.Tables["Suppliers"];
    DataRow[] rows = table.Select();

    // Print the value one column of each DataRow.
    for(int i = 0; i < rows.Length ; i++)
    {
        Console.WriteLine(rows[i]["CompanyName"]);
    }
}
Private Sub GetRows()
    ' Get the DataTable of a DataSet.
    Dim table As DataTable = DataSet1.Tables("Suppliers")
    Dim rows() As DataRow = table.Select()

    Dim i As Integer
    ' Print the value one column of each DataRow.
    For i = 0 to rows.GetUpperBound(0)
       Console.WriteLine(rows(i)("CompanyName"))
    Next i
End Sub

Comentários

Para garantir a ordem de classificação correta, especifique os critérios de classificação com Select(String, String) ou Select(String, String, DataViewRowState).To ensure the proper sort order, specify sort criteria with Select(String, String) or Select(String, String, DataViewRowState).

Veja também

Select(String)

Obtém uma matriz de todos os objetos DataRow que correspondem aos critérios de filtro.Gets an array of all DataRow objects that match the filter criteria.

public:
 cli::array <System::Data::DataRow ^> ^ Select(System::String ^ filterExpression);
public System.Data.DataRow[] Select (string filterExpression);
member this.Select : string -> System.Data.DataRow[]
Public Function Select (filterExpression As String) As DataRow()

Parâmetros

filterExpression
String

Os critérios a serem usados para filtrar as linhas.The criteria to use to filter the rows. Para ver exemplos de como filtrar linhas, consulte DataView RowFilter Syntax [C#].For examples on how to filter rows, see DataView RowFilter Syntax [C#].

Retornos

Uma matriz de objetos de DataRow.An array of DataRow objects.

Exemplos

O exemplo a seguir usa uma expressão de filtro para retornar uma matriz de objetos DataRow.The following example uses a filter expression to return an array of DataRow objects.

private void GetRowsByFilter()
{
    DataTable table = DataSet1.Tables["Orders"];
    // Presuming the DataTable has a column named Date.
    string expression;
    expression = "Date > #1/1/00#";
    DataRow[] foundRows;

    // Use the Select method to find all rows matching the filter.
    foundRows = table.Select(expression);

    // Print column 0 of each returned row.
    for(int i = 0; i < foundRows.Length; i ++)
    {
        Console.WriteLine(foundRows[i][0]);
    }
}
Private Sub GetRowsByFilter()
    
    Dim table As DataTable = DataSet1.Tables("Orders")

    ' Presuming the DataTable has a column named Date.
    Dim expression As String
    expression = "Date > #1/1/00#"
    Dim foundRows() As DataRow

    ' Use the Select method to find all rows matching the filter.
    foundRows = table.Select(expression)

    Dim i As Integer
    ' Print column 0 of each returned row.
    For i = 0 to foundRows.GetUpperBound(0)
       Console.WriteLine(foundRows(i)(0))
    Next i
End Sub

Comentários

Para criar o argumento filterExpression, use as mesmas regras que se aplicam ao valor da propriedade Expression da classe DataColumn para criar filtros.To create the filterExpression argument, use the same rules that apply to the DataColumn class's Expression property value for creating filters.

Para garantir a ordem de classificação correta, especifique os critérios de classificação com Select(String, String) ou Select(String, String, DataViewRowState).To ensure the proper sort order, specify sort criteria with Select(String, String) or Select(String, String, DataViewRowState).

Se a coluna no filtro contiver um valor nulo, ela não fará parte do resultado.If the column on the filter contains a null value, it will not be part of the result.

Veja também

Select(String, String)

Obtém uma matriz de todos os objetos DataRow que correspondem aos critérios de filtro, na ordem de classificação especificada.Gets an array of all DataRow objects that match the filter criteria, in the specified sort order.

public:
 cli::array <System::Data::DataRow ^> ^ Select(System::String ^ filterExpression, System::String ^ sort);
public System.Data.DataRow[] Select (string filterExpression, string sort);
member this.Select : string * string -> System.Data.DataRow[]
Public Function Select (filterExpression As String, sort As String) As DataRow()

Parâmetros

filterExpression
String

Os critérios a serem usados para filtrar as linhas.The criteria to use to filter the rows. Para ver exemplos de como filtrar linhas, consulte DataView RowFilter Syntax [C#].For examples on how to filter rows, see DataView RowFilter Syntax [C#].

sort
String

Uma cadeia de caracteres que especifica a direção da coluna e da classificação.A string specifying the column and sort direction.

Retornos

Uma matriz de objetos DataRow que correspondem à expressão de filtro.An array of DataRow objects matching the filter expression.

Exemplos

O exemplo a seguir usa uma expressão de filtro para retornar uma matriz de objetos DataRow.The following example uses a filter expression to return an array of DataRow objects.

using System;
using System.Data;

public class A {  

   public static void Main() {      
      DataTable table = new DataTable("Orders");
      table.Columns.Add("OrderID", typeof(Int32));
      table.Columns.Add("OrderQuantity", typeof(Int32));
      table.Columns.Add("CompanyName", typeof(string));      
      table.Columns.Add("Date", typeof(DateTime));

      DataRow newRow = table.NewRow();
      newRow["OrderID"] = 1;
      newRow["OrderQuantity"] = 3;
      newRow["CompanyName"] = "NewCompanyName";
      newRow["Date"] = "1979, 1, 31";

      // Add the row to the rows collection.
      table.Rows.Add(newRow);
      
      DataRow newRow2 = table.NewRow();
      newRow2["OrderID"] = 2;
      newRow2["OrderQuantity"] = 2;
      newRow2["CompanyName"] = "NewCompanyName1";
      table.Rows.Add(newRow2);

      DataRow newRow3 = table.NewRow();
      newRow3["OrderID"] = 3;
      newRow3["OrderQuantity"] = 2;
      newRow3["CompanyName"] = "NewCompanyName2";
      table.Rows.Add(newRow3);

      // Presuming the DataTable has a column named Date.
      string expression = "Date = '1/31/1979' or OrderID = 2";
      // string expression = "OrderQuantity = 2 and OrderID = 2";

      // Sort descending by column named CompanyName.
      string sortOrder = "CompanyName ASC";
      DataRow[] foundRows;

      // Use the Select method to find all rows matching the filter.
      foundRows = table.Select(expression, sortOrder);

      // Print column 0 of each returned row.
      for (int i = 0; i < foundRows.Length; i++)
         Console.WriteLine(foundRows[i][2]);
   }
}
Imports System.Data

Public Class A

   Public Shared Sub Main()
      Dim table As New DataTable("Orders")
      table.Columns.Add("OrderID", GetType(Int32))
      table.Columns.Add("OrderQuantity", GetType(Int32))
      table.Columns.Add("CompanyName", GetType(String))
      table.Columns.Add("Date", GetType(DateTime))

      Dim newRow As DataRow = table.NewRow()
      newRow("OrderID") = 1
      newRow("OrderQuantity") = 3
      newRow("CompanyName") = "NewCompanyName"
      newRow("Date") = "1979, 1, 31"

      ' Add the row to the rows collection.
      table.Rows.Add(newRow)

      Dim newRow2 As DataRow = table.NewRow()
      newRow2("OrderID") = 2
      newRow2("OrderQuantity") = 2
      newRow2("CompanyName") = "NewCompanyName1"
      table.Rows.Add(newRow2)

      Dim newRow3 As DataRow = table.NewRow()
      newRow3("OrderID") = 3
      newRow3("OrderQuantity") = 2
      newRow3("CompanyName") = "NewCompanyName2"
      table.Rows.Add(newRow3)

      ' Presuming the DataTable has a column named Date.
      Dim expression As String = "Date = '1/31/1979' or OrderID = 2"
      ' Dim expression As String = "OrderQuantity = 2 and OrderID = 2"

      ' Sort descending by column named CompanyName.
      Dim sortOrder As String = "CompanyName ASC"
      Dim foundRows As DataRow()

      ' Use the Select method to find all rows matching the filter.
      foundRows = table.[Select](expression, sortOrder)

      ' Print column 0 of each returned row.
      For i As Integer = 0 To foundRows.Length - 1
         Console.WriteLine(foundRows(i)(2))
      Next
   End Sub
End Class

Comentários

Para formar o argumento filterExpression, use as mesmas regras para criar o valor da propriedade Expression da classe DataColumn.To form the filterExpression argument, use the same rules for creating the DataColumn class's Expression property value. O argumento Sort também usa as mesmas regras para criar cadeias de Expression de classe.The Sort argument also uses the same rules for creating class's Expression strings.

Se a coluna no filtro contiver um valor nulo, ela não fará parte do resultado.If the column on the filter contains a null value, it will not be part of the result.

Veja também

Select(String, String, DataViewRowState)

Obtém uma matriz de todos os objetos DataRow que correspondem ao filtro, na ordem de classificação correspondente ao estado especificado.Gets an array of all DataRow objects that match the filter in the order of the sort that match the specified state.

public:
 cli::array <System::Data::DataRow ^> ^ Select(System::String ^ filterExpression, System::String ^ sort, System::Data::DataViewRowState recordStates);
public System.Data.DataRow[] Select (string filterExpression, string sort, System.Data.DataViewRowState recordStates);
member this.Select : string * string * System.Data.DataViewRowState -> System.Data.DataRow[]
Public Function Select (filterExpression As String, sort As String, recordStates As DataViewRowState) As DataRow()

Parâmetros

filterExpression
String

Os critérios a serem usados para filtrar as linhas.The criteria to use to filter the rows. Para ver exemplos de como filtrar linhas, consulte DataView RowFilter Syntax [C#].For examples on how to filter rows, see DataView RowFilter Syntax [C#].

sort
String

Uma cadeia de caracteres que especifica a direção da coluna e da classificação.A string specifying the column and sort direction.

recordStates
DataViewRowState

Um dos valores de DataViewRowState.One of the DataViewRowState values.

Retornos

Uma matriz de objetos de DataRow.An array of DataRow objects.

Exemplos

O exemplo a seguir usa uma expressão de filtro e um estado de registro para retornar uma matriz de objetos DataRow.The following example uses a filter expression and record state to return an array of DataRow objects.

private static void GetRowsByFilter()
{
    DataTable customerTable = new DataTable("Customers");
    // Add columns
    customerTable.Columns.Add("id", typeof(int));
    customerTable.Columns.Add("name", typeof(string));

    // Set PrimaryKey
    customerTable.Columns[ "id" ].Unique = true;
    customerTable.PrimaryKey = new DataColumn[] 
        { customerTable.Columns["id"] };

    // Add ten rows
    for(int id=1; id<=10; id++)
    {
        customerTable.Rows.Add(
            new object[] { id, string.Format("customer{0}", id) });
    }
    customerTable.AcceptChanges();

    // Add another ten rows
    for(int id=11; id<=20; id++)
    {
        customerTable.Rows.Add(
            new object[] { id, string.Format("customer{0}", id) });
    }

    string expression;
    string sortOrder;

    expression = "id > 5";
    // Sort descending by column named CompanyName.
    sortOrder = "name DESC";
    // Use the Select method to find all rows matching the filter.
    DataRow[] foundRows = 
        customerTable.Select(expression, sortOrder, 
        DataViewRowState.Added);

    PrintRows(foundRows, "filtered rows");

    foundRows = customerTable.Select();
    PrintRows(foundRows, "all rows");
}

private static void PrintRows(DataRow[] rows, string label)
{
    Console.WriteLine("\n{0}", label);
    if(rows.Length <= 0)
    {
        Console.WriteLine("no rows found");
        return;
    }
    foreach(DataRow row in rows)
    {
        foreach(DataColumn column in row.Table.Columns)
        {
            Console.Write("\table {0}", row[column]);
        }
        Console.WriteLine();
    }
}
Private Sub GetRowsByFilter()

    Dim customerTable As New DataTable("Customers")

    ' Add columns
    customerTable.Columns.Add("id", GetType(Integer))
    customerTable.Columns.Add("name", GetType(String))

    ' Set PrimaryKey
    customerTable.Columns("id").Unique = True
    customerTable.PrimaryKey = New DataColumn() _
        {customerTable.Columns("id")}

    ' add ten rows
    Dim id As Integer
    For id = 1 To 10
        customerTable.Rows.Add( _
        New Object() {id, String.Format("customer{0}", id)})
    Next id
    customerTable.AcceptChanges()

    ' add another ten rows
    For id = 11 To 20
        customerTable.Rows.Add( _
        New Object() {id, String.Format("customer{0}", id)})
    Next id

    Dim expression As String
    Dim sortOrder As String

    expression = "id > 5"
    ' Sort descending by CompanyName column.
    sortOrder = "name DESC"

    ' Use the Select method to find all rows matching the filter.
    Dim foundRows As DataRow() = _
        customerTable.Select(expression, sortOrder, _
        DataViewRowState.Added)

    PrintRows(foundRows, "filtered rows")

    foundRows = customerTable.Select()
    PrintRows(foundRows, "all rows")
End Sub

Private Sub PrintRows(ByVal rows() As DataRow, ByVal label As String)
    Console.WriteLine("\n{0}", label)
    If rows.Length <= 0 Then
        Console.WriteLine("no rows found")
        Exit Sub
    End If

    Dim row As DataRow
    Dim column As DataColumn
    For Each row In rows
        For Each column In row.Table.Columns
            Console.Write("\table {0}", row(column))
        Next column
        Console.WriteLine()
    Next row
End Sub

Comentários

Para formar o argumento filterExpression, use as mesmas regras para criar o valor da propriedade Expression da classe DataColumn.To form the filterExpression argument, use the same rules for creating the DataColumn class's Expression property value. O argumento Sort também usa as mesmas regras para criar cadeias de Expression de classe.The Sort argument also uses the same rules for creating class's Expression strings.

Se a coluna no filtro contiver um valor nulo, ela não fará parte do resultado.If the column on the filter contains a null value, it will not be part of the result.

Veja também

Aplica-se a