FetchAll Property (DbDataTable)

In This Topic

Determines whether data is requested from server entirely or partially.

Syntax

Visual Basic
C#


'Declaration Public Overridable Property FetchAll As Boolean


public virtual bool FetchAll {get; set;}

Property Value

If true, the data is requested when the DbDataTable is opened, otherwise records are fetched only when necessary.

Remarks

The FetchAll property allows you to optimize application behavior depending on circumstances. For example, consider a situation when user requests large amount of data to be displayed in a grid. When FetchAll is true, the whole dataset is retrieved from server at once, and while navigating through the dataset no server roundtrips are necessary. Thus application less depends on network speed and stability. When FetchAll is false, only minimal quantity of rows is requested at once, which leads to better initial response time and less network traffic.

Note that when FetchAll is true, fill operations can be asynchronous. Refer to NonBlocking property for more information.

When FetchAll is false, it could be useful to determine rows quantity with the QueryRecordCount property.

Example

The following example demonstrates how to use the FetchAll property.

csharp


static void UseDataTable(DbDataTable myDataTable, DbConnection myConnection, DataGrid dataGrid) { myDataTable.Connection = myConnection; myDataTable.SelectCommand = myConnection.CreateCommand(); myDataTable.SelectCommand.CommandText = "SELECT * FROM Test.Dept"; myDataTable.FetchAll = true; myDataTable.CachedUpdates = false; myDataTable.Active = true; dataGrid.DataSource = myDataTable; }

static void UseDataTable(DbDataTable myDataTable, DbConnection myConnection, DataGrid dataGrid) {

  myDataTable.Connection = myConnection;
  myDataTable.SelectCommand = myConnection.CreateCommand();
  myDataTable.SelectCommand.CommandText = "SELECT * FROM Test.Dept";
  myDataTable.FetchAll = true;
  myDataTable.CachedUpdates = false;
  myDataTable.Active = true;
  dataGrid.DataSource = myDataTable;
}

Visual Basic


Private Shared Sub UseDataTable(ByVal myDataTable As DbDataTable, ByVal myConnection As DbConnection, ByVal dataGrid As DataGrid) myDataTable.Connection = myConnection myDataTable.SelectCommand = myConnection.CreateCommand myDataTable.SelectCommand.CommandText = "SELECT * FROM Test.Dept" myDataTable.FetchAll = True myDataTable.CachedUpdates = False myDataTable.Active = True dataGrid.DataSource = myDataTable End Sub

Private Shared Sub UseDataTable(ByVal myDataTable As DbDataTable, ByVal myConnection As DbConnection, ByVal dataGrid As DataGrid)
  myDataTable.Connection = myConnection
  myDataTable.SelectCommand = myConnection.CreateCommand
  myDataTable.SelectCommand.CommandText = "SELECT * FROM Test.Dept"
  myDataTable.FetchAll = True
  myDataTable.CachedUpdates = False
  myDataTable.Active = True
  dataGrid.DataSource = myDataTable
End Sub

Reference

DbDataTable Class
DbDataTable Members
NonBlocking Property
QueryRecordCount Property

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