DataTable Класс

Определение

public ref class DataTable : System::ComponentModel::MarshalByValueComponent, System::ComponentModel::IListSource, System::ComponentModel::ISupportInitialize, System::ComponentModel::ISupportInitializeNotification, System::Runtime::Serialization::ISerializable, System::Xml::Serialization::IXmlSerializable

public ref class DataTable

public ref class DataTable : System::ComponentModel::MarshalByValueComponent, System::ComponentModel::IListSource, System::ComponentModel::ISupportInitialize, System::Runtime::Serialization::ISerializable

public ref class DataTable : System::ComponentModel::MarshalByValueComponent, System::ComponentModel::IListSource, System::ComponentModel::ISupportInitializeNotification, System::Runtime::Serialization::ISerializable, System::Xml::Serialization::IXmlSerializable

public class DataTable : System.ComponentModel.MarshalByValueComponent, System.ComponentModel.IListSource, System.ComponentModel.ISupportInitialize, System.ComponentModel.ISupportInitializeNotification, System.Runtime.Serialization.ISerializable, System.Xml.Serialization.IXmlSerializable

public class DataTable

[System.Serializable]
public class DataTable : System.ComponentModel.MarshalByValueComponent, System.ComponentModel.IListSource, System.ComponentModel.ISupportInitialize, System.Runtime.Serialization.ISerializable

[System.Serializable]
public class DataTable : System.ComponentModel.MarshalByValueComponent, System.ComponentModel.IListSource, System.ComponentModel.ISupportInitializeNotification, System.Runtime.Serialization.ISerializable, System.Xml.Serialization.IXmlSerializable

public class DataTable : System.ComponentModel.MarshalByValueComponent, System.ComponentModel.IListSource, System.ComponentModel.ISupportInitializeNotification, System.Runtime.Serialization.ISerializable, System.Xml.Serialization.IXmlSerializable

type DataTable = class
    inherit MarshalByValueComponent
    interface IListSource
    interface ISupportInitialize
    interface ISupportInitializeNotification
    interface ISerializable
    interface IXmlSerializable

type DataTable = class

type DataTable = class
    inherit MarshalByValueComponent
    interface IListSource
    interface ISupportInitialize
    interface ISerializable

type DataTable = class
    inherit MarshalByValueComponent
    interface IListSource
    interface ISupportInitializeNotification
    interface ISupportInitialize
    interface ISerializable
    interface IXmlSerializable

type DataTable = class
    inherit MarshalByValueComponent
    interface IListSource
    interface ISupportInitializeNotification
    interface ISerializable
    interface IXmlSerializable
    interface ISupportInitialize

Public Class DataTable
Inherits MarshalByValueComponent
Implements IListSource, ISerializable, ISupportInitialize, ISupportInitializeNotification, IXmlSerializable

Public Class DataTable

Public Class DataTable
Inherits MarshalByValueComponent
Implements IListSource, ISerializable, ISupportInitialize

Public Class DataTable
Inherits MarshalByValueComponent
Implements IListSource, ISerializable, ISupportInitializeNotification, IXmlSerializable

Наследование

Object

MarshalByValueComponent

DataTable

Наследование

Object

DataTable

Производный

System.Data.TypedTableBase<T>

Атрибуты

SerializableAttribute

Реализации

IListSource ISupportInitialize ISupportInitializeNotification ISerializable IXmlSerializable

Примеры

В следующем примере создаются два DataTable объектов и один DataRelationный объект и добавляются новые объекты в DataSet.The following example creates two DataTable objects and one DataRelation object, and adds the new objects to a DataSet. Затем таблицы отображаются в элементе управления DataGridView.The tables are then displayed in a DataGridView control.

// Put the next line into the Declarations section.
private System.Data.DataSet dataSet;

private void MakeDataTables()
{
    // Run all of the functions.
    MakeParentTable();
    MakeChildTable();
    MakeDataRelation();
    BindToDataGrid();
}

private void MakeParentTable()
{
    // Create a new DataTable.
    System.Data.DataTable table = new DataTable("ParentTable");
    // Declare variables for DataColumn and DataRow objects.
    DataColumn column;
    DataRow row;

    // Create new DataColumn, set DataType,
    // ColumnName and add to DataTable.
    column = new DataColumn();
    column.DataType = System.Type.GetType("System.Int32");
    column.ColumnName = "id";
    column.ReadOnly = true;
    column.Unique = true;
    // Add the Column to the DataColumnCollection.
    table.Columns.Add(column);

    // Create second column.
    column = new DataColumn();
    column.DataType = System.Type.GetType("System.String");
    column.ColumnName = "ParentItem";
    column.AutoIncrement = false;
    column.Caption = "ParentItem";
    column.ReadOnly = false;
    column.Unique = false;
    // Add the column to the table.
    table.Columns.Add(column);

    // Make the ID column the primary key column.
    DataColumn[] PrimaryKeyColumns = new DataColumn[1];
    PrimaryKeyColumns[0] = table.Columns["id"];
    table.PrimaryKey = PrimaryKeyColumns;

    // Instantiate the DataSet variable.
    dataSet = new DataSet();
    // Add the new DataTable to the DataSet.
    dataSet.Tables.Add(table);

    // Create three new DataRow objects and add
    // them to the DataTable
    for (int i = 0; i<= 2; i++)
    {
        row = table.NewRow();
        row["id"] = i;
        row["ParentItem"] = "ParentItem " + i;
        table.Rows.Add(row);
    }
}

private void MakeChildTable()
{
    // Create a new DataTable.
    DataTable table = new DataTable("childTable");
    DataColumn column;
    DataRow row;

    // Create first column and add to the DataTable.
    column = new DataColumn();
    column.DataType= System.Type.GetType("System.Int32");
    column.ColumnName = "ChildID";
    column.AutoIncrement = true;
    column.Caption = "ID";
    column.ReadOnly = true;
    column.Unique = true;

    // Add the column to the DataColumnCollection.
    table.Columns.Add(column);

    // Create second column.
    column = new DataColumn();
    column.DataType= System.Type.GetType("System.String");
    column.ColumnName = "ChildItem";
    column.AutoIncrement = false;
    column.Caption = "ChildItem";
    column.ReadOnly = false;
    column.Unique = false;
    table.Columns.Add(column);

    // Create third column.
    column = new DataColumn();
    column.DataType= System.Type.GetType("System.Int32");
    column.ColumnName = "ParentID";
    column.AutoIncrement = false;
    column.Caption = "ParentID";
    column.ReadOnly = false;
    column.Unique = false;
    table.Columns.Add(column);

    dataSet.Tables.Add(table);

    // Create three sets of DataRow objects,
    // five rows each, and add to DataTable.
    for(int i = 0; i <= 4; i ++)
    {
        row = table.NewRow();
        row["childID"] = i;
        row["ChildItem"] = "Item " + i;
        row["ParentID"] = 0 ;
        table.Rows.Add(row);
    }
    for(int i = 0; i <= 4; i ++)
    {
        row = table.NewRow();
        row["childID"] = i + 5;
        row["ChildItem"] = "Item " + i;
        row["ParentID"] = 1 ;
        table.Rows.Add(row);
    }
    for(int i = 0; i <= 4; i ++)
    {
        row = table.NewRow();
        row["childID"] = i + 10;
        row["ChildItem"] = "Item " + i;
        row["ParentID"] = 2 ;
        table.Rows.Add(row);
    }
}

private void MakeDataRelation()
{
    // DataRelation requires two DataColumn
    // (parent and child) and a name.
    DataColumn parentColumn =
        dataSet.Tables["ParentTable"].Columns["id"];
    DataColumn childColumn =
        dataSet.Tables["ChildTable"].Columns["ParentID"];
    DataRelation relation = new
        DataRelation("parent2Child", parentColumn, childColumn);
    dataSet.Tables["ChildTable"].ParentRelations.Add(relation);
}

private void BindToDataGrid()
{
    // Instruct the DataGrid to bind to the DataSet, with the
    // ParentTable as the topmost DataTable.
    dataGrid1.SetDataBinding(dataSet,"ParentTable");
}

' Put the next line into the Declarations section.
private dataSet As DataSet 
 
Private Sub MakeDataTables()
    ' Run all of the functions. 
    MakeParentTable()
    MakeChildTable()
    MakeDataRelation()
    BindToDataGrid()
End Sub
 
Private Sub MakeParentTable()
    ' Create a new DataTable.
    Dim table As New DataTable("ParentTable")

    ' Declare variables for DataColumn and DataRow objects.
    Dim column As DataColumn 
    Dim row As DataRow 
 
    ' Create new DataColumn, set DataType, ColumnName 
    ' and add to DataTable.    
    column = New DataColumn()
    column.DataType = System.Type.GetType("System.Int32")
    column.ColumnName = "id"
    column.ReadOnly = True
    column.Unique = True

    ' Add the Column to the DataColumnCollection.
    table.Columns.Add(column)
 
    ' Create second column.
    column = New DataColumn()
    column.DataType = System.Type.GetType("System.String")
    column.ColumnName = "ParentItem"
    column.AutoIncrement = False
    column.Caption = "ParentItem"
    column.ReadOnly = False
    column.Unique = False

    ' Add the column to the table.
    table.Columns.Add(column)
 
    ' Make the ID column the primary key column.
    Dim PrimaryKeyColumns(0) As DataColumn
    PrimaryKeyColumns(0)= table.Columns("id")
    table.PrimaryKey = PrimaryKeyColumns
 
    ' Instantiate the DataSet variable.
    dataSet = New DataSet()

    ' Add the new DataTable to the DataSet.
    dataSet.Tables.Add(table)
 
    ' Create three new DataRow objects and add 
    ' them to the DataTable
    Dim i As Integer
    For i = 0 to 2
       row = table.NewRow()
       row("id") = i
       row("ParentItem") = "ParentItem " + i.ToString()
       table.Rows.Add(row)
    Next i
End Sub
 
Private Sub MakeChildTable()
    ' Create a new DataTable.
    Dim table As New DataTable("childTable")
    Dim column As DataColumn 
    Dim row As DataRow 
 
    ' Create first column and add to the DataTable.
    column = New DataColumn()
    column.DataType= System.Type.GetType("System.Int32")
    column.ColumnName = "ChildID"
    column.AutoIncrement = True
    column.Caption = "ID"
    column.ReadOnly = True
    column.Unique = True

    ' Add the column to the DataColumnCollection.
    table.Columns.Add(column)
 
    ' Create second column.
    column = New DataColumn()
    column.DataType= System.Type.GetType("System.String")
    column.ColumnName = "ChildItem"
    column.AutoIncrement = False
    column.Caption = "ChildItem"
    column.ReadOnly = False
    column.Unique = False
    table.Columns.Add(column)
 
    ' Create third column.
    column = New DataColumn()
    column.DataType= System.Type.GetType("System.Int32")
    column.ColumnName = "ParentID"
    column.AutoIncrement = False
    column.Caption = "ParentID"
    column.ReadOnly = False
    column.Unique = False
    table.Columns.Add(column)
 
    dataSet.Tables.Add(table)

    ' Create three sets of DataRow objects, five rows each, 
    ' and add to DataTable.
    Dim i As Integer
    For i = 0 to 4
       row = table.NewRow()
       row("childID") = i
       row("ChildItem") = "Item " + i.ToString()
       row("ParentID") = 0 
       table.Rows.Add(row)
    Next i
    For i = 0 to 4
       row = table.NewRow()
       row("childID") = i + 5
       row("ChildItem") = "Item " + i.ToString()
       row("ParentID") = 1 
       table.Rows.Add(row)
    Next i
    For i = 0 to 4
       row = table.NewRow()
       row("childID") = i + 10
       row("ChildItem") = "Item " + i.ToString()
       row("ParentID") = 2 
       table.Rows.Add(row)
    Next i
End Sub
 
Private Sub MakeDataRelation()
    ' DataRelation requires two DataColumn 
    ' (parent and child) and a name.
    Dim parentColumn As DataColumn = _
        dataSet.Tables("ParentTable").Columns("id")
    Dim childColumn As DataColumn = _
        dataSet.Tables("ChildTable").Columns("ParentID")
    Dim relation As DataRelation = new _
        DataRelation("parent2Child", parentColumn, childColumn)
    dataSet.Tables("ChildTable").ParentRelations.Add(relation)
End Sub
 
Private Sub BindToDataGrid()
    ' Instruct the DataGrid to bind to the DataSet, with the 
    ' ParentTable as the topmost DataTable.
    DataGrid1.SetDataBinding(dataSet,"ParentTable")
End Sub
 

В этом примере показано, как создать таблицу данных вручную с конкретными определениями схемы:This sample demonstrates how to create a DataTable manually with specific schema definitions:

• Создайте несколько таблиц DataTable и определите начальные столбцы.Create multiple DataTables and define the initial columns.

• Создайте ограничения таблицы.Create the table constraints.

• Вставьте значения и отобразите таблицы.Insert the values and display the tables.

• Создайте столбцы выражений и отобразите таблицы.Create the expression columns and display the tables.

C#Visual Basic проекты с этим примером кода можно найти в примерах кода для разработчиков.C# and Visual Basic projects with this code sample can be found on Developer Code Samples.

using System;
using System.Data;

class Program {
   static void Main(string[] args) {
      // Create two tables and add them into the DataSet
      DataTable orderTable = CreateOrderTable();
      DataTable orderDetailTable = CreateOrderDetailTable();
      DataSet salesSet = new DataSet();
      salesSet.Tables.Add(orderTable);
      salesSet.Tables.Add(orderDetailTable);

      // Set the relations between the tables and create the related constraint.
      salesSet.Relations.Add("OrderOrderDetail", orderTable.Columns["OrderId"], orderDetailTable.Columns["OrderId"], true);

      Console.WriteLine("After creating the foreign key constriant, you will see the following error if inserting order detail with the wrong OrderId: ");
      try {
         DataRow errorRow = orderDetailTable.NewRow();
         errorRow[0] = 1;
         errorRow[1] = "O0007";
         orderDetailTable.Rows.Add(errorRow);
      } catch (Exception e) {
         Console.WriteLine(e.Message);
      }
      Console.WriteLine();

      // Insert the rows into the table
      InsertOrders(orderTable);
      InsertOrderDetails(orderDetailTable);

      Console.WriteLine("The initial Order table.");
      ShowTable(orderTable);

      Console.WriteLine("The OrderDetail table.");
      ShowTable(orderDetailTable);

      // Use the Aggregate-Sum on the child table column to get the result.
      DataColumn colSub = new DataColumn("SubTotal", typeof(Decimal), "Sum(Child.LineTotal)");
      orderTable.Columns.Add(colSub);

      // Compute the tax by referencing the SubTotal expression column.
      DataColumn colTax = new DataColumn("Tax", typeof(Decimal), "SubTotal*0.1");
      orderTable.Columns.Add(colTax);

      // If the OrderId is 'Total', compute the due on all orders; or compute the due on this order.
      DataColumn colTotal = new DataColumn("TotalDue", typeof(Decimal), "IIF(OrderId='Total',Sum(SubTotal)+Sum(Tax),SubTotal+Tax)");
      orderTable.Columns.Add(colTotal);

      DataRow row = orderTable.NewRow();
      row["OrderId"] = "Total";
      orderTable.Rows.Add(row);

      Console.WriteLine("The Order table with the expression columns.");
      ShowTable(orderTable);

      Console.WriteLine("Press any key to exit.....");
      Console.ReadKey();
   }

   private static DataTable CreateOrderTable() {
      DataTable orderTable = new DataTable("Order");

      // Define one column.
      DataColumn colId = new DataColumn("OrderId", typeof(String));
      orderTable.Columns.Add(colId);

      DataColumn colDate = new DataColumn("OrderDate", typeof(DateTime));
      orderTable.Columns.Add(colDate);

      // Set the OrderId column as the primary key.
      orderTable.PrimaryKey = new DataColumn[] { colId };

      return orderTable;
   }

   private static DataTable CreateOrderDetailTable() {
      DataTable orderDetailTable = new DataTable("OrderDetail");

      // Define all the columns once.
      DataColumn[] cols ={
                                  new DataColumn("OrderDetailId",typeof(Int32)),
                                  new DataColumn("OrderId",typeof(String)),
                                  new DataColumn("Product",typeof(String)),
                                  new DataColumn("UnitPrice",typeof(Decimal)),
                                  new DataColumn("OrderQty",typeof(Int32)),
                                  new DataColumn("LineTotal",typeof(Decimal),"UnitPrice*OrderQty")
                              };

      orderDetailTable.Columns.AddRange(cols);
      orderDetailTable.PrimaryKey = new DataColumn[] { orderDetailTable.Columns["OrderDetailId"] };
     return orderDetailTable;
   }

   private static void InsertOrders(DataTable orderTable) {
      // Add one row once.
      DataRow row1 = orderTable.NewRow();
      row1["OrderId"] = "O0001";
      row1["OrderDate"] = new DateTime(2013, 3, 1);
      orderTable.Rows.Add(row1);

      DataRow row2 = orderTable.NewRow();
      row2["OrderId"] = "O0002";
      row2["OrderDate"] = new DateTime(2013, 3, 12);
      orderTable.Rows.Add(row2);

      DataRow row3 = orderTable.NewRow();
      row3["OrderId"] = "O0003";
      row3["OrderDate"] = new DateTime(2013, 3, 20);
      orderTable.Rows.Add(row3);
   }

   private static void InsertOrderDetails(DataTable orderDetailTable) {
      // Use an Object array to insert all the rows .
      // Values in the array are matched sequentially to the columns, based on the order in which they appear in the table.
      Object[] rows = {
                                 new Object[]{1,"O0001","Mountain Bike",1419.5,36},
                                 new Object[]{2,"O0001","Road Bike",1233.6,16},
                                 new Object[]{3,"O0001","Touring Bike",1653.3,32},
                                 new Object[]{4,"O0002","Mountain Bike",1419.5,24},
                                 new Object[]{5,"O0002","Road Bike",1233.6,12},
                                 new Object[]{6,"O0003","Mountain Bike",1419.5,48},
                                 new Object[]{7,"O0003","Touring Bike",1653.3,8},
                             };

      foreach (Object[] row in rows) {
         orderDetailTable.Rows.Add(row);
      }
   }

   private static void ShowTable(DataTable table) {
      foreach (DataColumn col in table.Columns) {
         Console.Write("{0,-14}", col.ColumnName);
      }
      Console.WriteLine();

      foreach (DataRow row in table.Rows) {
         foreach (DataColumn col in table.Columns) {
            if (col.DataType.Equals(typeof(DateTime)))
               Console.Write("{0,-14:d}", row[col]);
            else if (col.DataType.Equals(typeof(Decimal)))
               Console.Write("{0,-14:C}", row[col]);
            else
               Console.Write("{0,-14}", row[col]);
         }
         Console.WriteLine();
      }
      Console.WriteLine();
   }
}

Imports System.Data

Class Program
   Public Shared Sub Main(args As String())
      ' Create two tables and add them into the DataSet
      Dim orderTable As DataTable = CreateOrderTable()
      Dim orderDetailTable As DataTable = CreateOrderDetailTable()
      Dim salesSet As New DataSet()
      salesSet.Tables.Add(orderTable)
      salesSet.Tables.Add(orderDetailTable)

      ' Set the relations between the tables and create the related constraint.
      salesSet.Relations.Add("OrderOrderDetail", orderTable.Columns("OrderId"), orderDetailTable.Columns("OrderId"), True)

      Console.WriteLine("After creating the foreign key constriant, you will see the following error if inserting order detail with the wrong OrderId: ")
      Try
         Dim errorRow As DataRow = orderDetailTable.NewRow()
         errorRow(0) = 1
         errorRow(1) = "O0007"
         orderDetailTable.Rows.Add(errorRow)
      Catch e As Exception
         Console.WriteLine(e.Message)
      End Try
      Console.WriteLine()

      ' Insert the rows into the table
      InsertOrders(orderTable)
      InsertOrderDetails(orderDetailTable)

      Console.WriteLine("The initial Order table.")
      ShowTable(orderTable)

      Console.WriteLine("The OrderDetail table.")
      ShowTable(orderDetailTable)

      ' Use the Aggregate-Sum on the child table column to get the result.
      Dim colSub As New DataColumn("SubTotal", GetType([Decimal]), "Sum(Child.LineTotal)")
      orderTable.Columns.Add(colSub)

      ' Compute the tax by referencing the SubTotal expression column.
      Dim colTax As New DataColumn("Tax", GetType([Decimal]), "SubTotal*0.1")
      orderTable.Columns.Add(colTax)

      ' If the OrderId is 'Total', compute the due on all orders; or compute the due on this order.
      Dim colTotal As New DataColumn("TotalDue", GetType([Decimal]), "IIF(OrderId='Total',Sum(SubTotal)+Sum(Tax),SubTotal+Tax)")
      orderTable.Columns.Add(colTotal)

      Dim row As DataRow = orderTable.NewRow()
      row("OrderId") = "Total"
      orderTable.Rows.Add(row)

      Console.WriteLine("The Order table with the expression columns.")
      ShowTable(orderTable)

      Console.WriteLine("Press any key to exit.....")
      Console.ReadKey()
   End Sub

   Private Shared Function CreateOrderTable() As DataTable
      Dim orderTable As New DataTable("Order")

      ' Define one column.
      Dim colId As New DataColumn("OrderId", GetType([String]))
      orderTable.Columns.Add(colId)

      Dim colDate As New DataColumn("OrderDate", GetType(DateTime))
      orderTable.Columns.Add(colDate)

      ' Set the OrderId column as the primary key.
      orderTable.PrimaryKey = New DataColumn() {colId}

      Return orderTable
   End Function

   Private Shared Function CreateOrderDetailTable() As DataTable
      Dim orderDetailTable As New DataTable("OrderDetail")

      ' Define all the columns once.
      Dim cols As DataColumn() = {New DataColumn("OrderDetailId", GetType(Int32)), New DataColumn("OrderId", GetType([String])), New DataColumn("Product", GetType([String])), New DataColumn("UnitPrice", GetType([Decimal])), New DataColumn("OrderQty", GetType(Int32)), New DataColumn("LineTotal", GetType([Decimal]), "UnitPrice*OrderQty")}

      orderDetailTable.Columns.AddRange(cols)
      orderDetailTable.PrimaryKey = New DataColumn() {orderDetailTable.Columns("OrderDetailId")}
      Return orderDetailTable
   End Function

   Private Shared Sub InsertOrders(orderTable As DataTable)
      ' Add one row once.
      Dim row1 As DataRow = orderTable.NewRow()
      row1("OrderId") = "O0001"
      row1("OrderDate") = New DateTime(2013, 3, 1)
      orderTable.Rows.Add(row1)

      Dim row2 As DataRow = orderTable.NewRow()
      row2("OrderId") = "O0002"
      row2("OrderDate") = New DateTime(2013, 3, 12)
      orderTable.Rows.Add(row2)

      Dim row3 As DataRow = orderTable.NewRow()
      row3("OrderId") = "O0003"
      row3("OrderDate") = New DateTime(2013, 3, 20)
      orderTable.Rows.Add(row3)
   End Sub

   Private Shared Sub InsertOrderDetails(orderDetailTable As DataTable)
      ' Use an Object array to insert all the rows .
      ' Values in the array are matched sequentially to the columns, based on the order in which they appear in the table.
      Dim rows As [Object]() = {New [Object]() {1, "O0001", "Mountain Bike", 1419.5, 36}, New [Object]() {2, "O0001", "Road Bike", 1233.6, 16}, New [Object]() {3, "O0001", "Touring Bike", 1653.3, 32}, New [Object]() {4, "O0002", "Mountain Bike", 1419.5, 24}, New [Object]() {5, "O0002", "Road Bike", 1233.6, 12}, New [Object]() {6, "O0003", "Mountain Bike", 1419.5, 48}, _
         New [Object]() {7, "O0003", "Touring Bike", 1653.3, 8}}

      For Each row As [Object]() In rows
         orderDetailTable.Rows.Add(row)
      Next
   End Sub

   Private Shared Sub ShowTable(table As DataTable)
      For Each col As DataColumn In table.Columns
         Console.Write("{0,-14}", col.ColumnName)
      Next
      Console.WriteLine()

      For Each row As DataRow In table.Rows
         For Each col As DataColumn In table.Columns
            If col.DataType.Equals(GetType(DateTime)) Then
               Console.Write("{0,-14:d}", row(col))
            ElseIf col.DataType.Equals(GetType([Decimal])) Then
               Console.Write("{0,-14:C}", row(col))
            Else
               Console.Write("{0,-14}", row(col))
            End If
         Next
         Console.WriteLine()
      Next
      Console.WriteLine()
   End Sub
End Class

Комментарии

DataTable является центральным объектом в библиотеке ADO.NET.The DataTable is a central object in the ADO.NET library. Другие объекты, использующие DataTable, включают DataSet и DataView.Other objects that use the DataTable include the DataSet and the DataView.

При доступе к DataTable объектам Обратите внимание, что они чувствительны к регистру.When accessing DataTable objects, note that they are conditionally case sensitive. Например, если один DataTable имеет имя «Mydatatable», а другой — «Mydatatable», то строка, используемая для поиска одной из таблиц, рассматривается с учетом регистра.For example, if one DataTable is named "mydatatable" and another is named "Mydatatable", a string used to search for one of the tables is regarded as case sensitive. Однако если "Mydatatable" существует, а "Mydatatable" — нет, то строка поиска считается нечувствительной к регистру.However, if "mydatatable" exists and "Mydatatable" does not, the search string is regarded as case insensitive. DataSet может содержать два DataTable объектов, имеющих одно и то же значение свойства TableName, но разные Namespace значения свойств.A DataSet can contain two DataTable objects that have the same TableName property value but different Namespace property values. Дополнительные сведения о работе с объектами DataTable см. в разделе Создание таблицыданных.For more information about working with DataTable objects, see Creating a DataTable.

При создании DataTable программным способом необходимо сначала определить его схему, добавив DataColumn объекты в DataColumnCollection (доступ к которому осуществляется через свойство Columns).If you are creating a DataTable programmatically, you must first define its schema by adding DataColumn objects to the DataColumnCollection (accessed through the Columns property). Дополнительные сведения о добавлении DataColumn объектов см. в разделе Добавление столбцов в таблицуданных.For more information about adding DataColumn objects, see Adding Columns to a DataTable.

Чтобы добавить строки в DataTable, необходимо сначала использовать метод NewRow, чтобы получить новый объект DataRow.To add rows to a DataTable, you must first use the NewRow method to return a new DataRow object. Метод NewRow возвращает строку со схемой DataTable, так как она определена DataColumnCollectionом таблицы.The NewRow method returns a row with the schema of the DataTable, as it is defined by the table's DataColumnCollection. Максимальное число строк, которое может хранить DataTable, — 16 777 216.The maximum number of rows that a DataTable can store is 16,777,216. Дополнительные сведения см. в разделе Добавление данных в таблицу DataTable.For more information, see Adding Data to a DataTable.

DataTable также содержит коллекцию объектов Constraint, которые можно использовать для обеспечения целостности данных.The DataTable also contains a collection of Constraint objects that can be used to ensure the integrity of the data. Дополнительные сведения см. в разделе ограничения DataTable.For more information, see DataTable Constraints.

Существует много DataTable событий, которые можно использовать для определения времени внесения изменений в таблицу.There are many DataTable events that can be used to determine when changes are made to a table. К ним относятся RowChanged, RowChanging, RowDeleting и RowDeleted.These include RowChanged, RowChanging, RowDeleting, and RowDeleted. Дополнительные сведения о событиях, которые можно использовать с DataTable, см. в разделе Обработка событий DataTable.For more information about the events that can be used with a DataTable, see Handling DataTable Events.

При создании экземпляра DataTable для некоторых свойств чтения и записи задаются начальные значения.When an instance of DataTable is created, some of the read/write properties are set to initial values. Список этих значений см. в разделе конструктора DataTable.DataTable.For a list of these values, see the DataTable.DataTable constructor topic.

Конструкторы

Поля

Свойства

Методы

События

Явные реализации интерфейса

Методы расширения

Применяется к

Потокобезопасность

Этот тип является надежным для многопоточных операций чтения.This type is safe for multithreaded read operations. Необходимо синхронизировать любые операции записи.You must synchronize any write operations.

Дополнительно

• DataTablesDataTables