HOW TO: Locate a Specified DataRow by Using the Find Method of DataRowCollection in Visual Basic .NET

This article refers to the following Microsoft .NET Framework Class Library namespace:
  • System.Data

IN THIS TASK

This step-by-step article describes how to locate a specified DataRow object by using the Find method of the DataRowCollection.
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Additional Information About the Find Method

The Find method queries the primary key column of the DataTable, and locates the record that exactly matches the value that is passed in the search criteria. If the DataTable does not have a primary key, a MissingPrimaryKeyException is raised. The Find method has the following limitations:
  • The Find method is not case sensitive.
  • You cannot use Wildcard characters in the Find method. For example, when you use the following code, you may not find all the rows starting with Ch. Instead, you receive the row with the primary key value Ch%.
            myDataRow = myDataTable.Rows.Find("Ch%")
The Find method returns a DataRow that matches the search criteria. When no match is found, an empty DataRow object is returned. Using Is Nothing, you can detect the results of the Find method.

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Sample Code

  1. Create a new Visual Basic .NET Console Application project. By default, Module1.vb is created.
  2. Replace the existing code in Module1.vb with the following code:
    Imports System.Data
    Imports System.Data.SqlClient

    Module Module1

    Sub Main()
    ' Open connection.
    Dim cn As SqlConnection
    cn = New SqlConnection("User ID=sa;Initial Catalog=pubs;Data Source=mySQLServerName")

    ' Create DataAdaptor.
    Dim da As SqlDataAdapter
    da = New SqlDataAdapter("Select * from Employee", cn)

    ' Create a Dataset.
    Dim ds As DataSet
    ds = New DataSet()

    ' Get Schema such as primary key from the database.
    da.FillSchema(ds, SchemaType.Mapped, "Employee")

    'Get the data from database.
    da.Fill(ds, "Employee")

    ' DataRow to collect result of Find method.
    Dim dr As DataRow

    ' Find Employee with specified ID.
    Console.WriteLine("Searching for Employee ID = KFJ64308F")
    dr = ds.Tables("Employee").Rows.Find("KFJ64308F")
    ' Check whether the search returned any result.
    If Not (dr Is Nothing) Then
    Console.WriteLine("First Name is : {0}", dr("fname"))
    Else
    Console.WriteLine("No Matching Rows Found.")
    End If

    ' Try to use wildcard character.
    Console.WriteLine("Searching for all Employees with Employee ID starting with K (Wildcard K%)")
    dr = ds.Tables("Employee").Rows.Find("K%")
    ' Check whether the search returned any result.
    If Not (dr Is Nothing) Then
    Console.WriteLine("First Name is : {0}", dr("fname"))
    Else
    Console.WriteLine("No Matching Rows found with specified search criteria.")
    End If
    Console.ReadLine()
    End Sub

    End Module
  3. Modify the connection string as appropriate for your environment.
  4. On the Debug menu, click
    Start to run the application.
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Troubleshoot

The MissingPrimaryKeyException exception is thrown when you try to access a row in a table that does not have a primary key column.


For more information about MissingPrimaryKeyException, see the following Microsoft Developer Network (MSDN) Web site:back to the top

References

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
310373 PRB: DataAdapter.Fill Does Not Set All of the Properties
For more information, see the Microsoft .NET Framework SDK Documentation or MSDN on-line help.



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Properties

Article ID: 305561 - Last Review: Mar 23, 2009 - Revision: 1

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