DataTable.Select Method (String) (System.Data)

Select Method (String)

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This page is specific to

Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

DataTable..::.Select Method (String)

Gets an array of all DataRow objects that match the filter criteria in order of primary key (or lacking one, order of addition.)

Namespace: System.Data
Assembly: System.Data (in System.Data.dll)

Syntax

Visual Basic (Declaration)

Public Function Select ( _
    filterExpression As String _
) As DataRow()

Visual Basic (Usage)

Dim instance As DataTable
Dim filterExpression As String
Dim returnValue As DataRow()

returnValue = instance.Select(filterExpression)

public DataRow[] Select(
    string filterExpression
)

Visual C++

public:
array<DataRow^>^ Select(
    String^ filterExpression
)

JScript

public function Select(
    filterExpression : String
) : DataRow[]

Parameters

filterExpression: Type: System..::.String
The criteria to use to filter the rows.

Return Value

Type: array<System.Data..::.DataRow>[]()[]
An array of DataRow objects.

Remarks

To create the filterExpression argument, use the same rules that apply to the DataColumn class's Expression property value for creating filters.

Examples

The following example uses a filter expression to return an array of DataRow objects.

Visual Basic

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

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]);
    }
}

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Reference

DataTable Class

DataTable Members

Select Overload

System.Data Namespace

CaseSensitive

Other Resources

DataTables (ADO.NET)

Tags

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Flag as ContentBug

Stack Overflow

ParaMoxie ... Stanley Roark | Edit | Show History

- Stack Overflow can be caused by having combination of:

1) too many Rows in the DataTable

2) too many OR/AND expressions in the filter string (also see

http://forums.microsoft.com/msdn/ShowPost.aspx?PostID=3033750&SiteID=1 )

3) too long colomn names.

- I tried catching the exception and for some reason it could not be caught. Proabbly because this is an infinite loop/recurssion type of exception and process is not around to even throw the exception.

- The definition of "too long" and "too many" is not clear.

- Following program can be used to cause stack overflow exception. Set different values for the factors in the program and test to see results:

using System;

using System.Collections.Generic;

using System.Text;

using System.Data;

namespace Datatable Tester

class Program

static void Main(string[] args)

DataTable dt = newDataTable("test");

string filter = "";

/* following factors could cause the overflow */

string cname = "col";

int colmax = 50;

int rowsmax = 50;

int linesmax = 40;

int factor = 20;

for (int col = 1 ;col <= colmax ;col ++)

dt.Columns.Add(cname + col.ToString());

for ( int rows = 0 ;rows< rowsmax; rows++)

dt.Rows.Add(123411, 234122, 123423, 12341244, 1234, 13412346, 123417, 12341, 123419);

for(int num = 0; num < linesmax; num++)

for (int i =1 ; i <= colmax; i++)

filter = filter +

" " + cname + i.ToString() + " = " + (i * factor).ToString() + " OR ";

filter = filter +

" " + cname + "1 = null";

/* Even though the exception is handled, its not getting caught */

try {

DataRow[] dr = dt.Select(filter);

catch (Exception se) {

Console.WriteLine(se.Message);