How to select top n rows from a datatable dataview in ASP NET

Question

How to the select top n rows from a datatable dataview in ASP NET  Currently I am using the following code  passing the table and number of rows to get the records  Is there a better way   public DataTable  SelectTopDataRow DataTable dt  int count         DataTable dtn   dt Clone         for  int i   0  i  lt  count  i                    dtn ImportRow dt Rows i                 return dtn

User · Answer

You could modify the query  If you are using SQL Server at the back  you can use Select top n query for such need  The current implements fetch the whole data from database  Selecting only the required number of rows will give you a performance boost as well

User · Answer

public DataTable TopDataRow DataTable dt  int count                DataTable dtn   dt Clone            int i   0          foreach  DataRow row in dt Rows                        if  i  lt  count                                dtn ImportRow row                   i                              if  i  gt  count                  break                    return dtn

User · Answer

In framework 3 5  dt Rows Cast lt System Data DataRow gt    Take n   Otherwise the way you mentioned

User · Answer

Data view is good Feature of data table   We can filter the data table as per our requirements using data view   Below Functions is After binding data table to list box data source then filter by text box control     this condition you can change as per your needs  Contains txtSearch Text Trim       Private Sub BindClients       okcl   0      sql    Select   from Client Order By cname              Dim dacli As New SqlClient SqlDataAdapter     Dim cmd As New SqlClient SqlCommand       cmd CommandText   sql     cmd CommandType   CommandType Text     dacli SelectCommand   cmd     dacli SelectCommand Connection   Me sqlcn     Dim dtcli As New DataTable     dacli Fill dtcli      dacli Fill dataTableClients      lstboxc DataSource   dataTableClients     lstboxc DisplayMember    cname      lstboxc ValueMember    ccode      okcl   1      If dtcli Rows Count  gt  0 Then         ccode   dtcli Rows 0   ccode           Call ClientDispData1       End If End Sub  Private Sub FilterClients                Dim query As EnumerableRowCollection Of DataRow    From dataTableClients In      dataTableClients AsEnumerable   Where dataTableClients Field Of String         cname   Contains txtSearch Text Trim    Order By dataTableClients Field Of      String   cname   Select dataTableClients      Dim dataView As DataView   query AsDataView       lstboxc DataSource   dataView     lstboxc DisplayMember    cname      lstboxc ValueMember    ccode      okcl   1     If dataTableClients Rows Count  gt  0 Then         ccode   dataTableClients Rows 0   ccode           Call ClientDispData1       End If End Sub

User · Answer

I just used Midhat s answer but appended CopyToDataTable   on the end   The code below is an extension to the answer that I used to quickly enable some paging   int pageNum   1  int pageSize   25   DataTable dtPage   dt Rows Cast lt System Data DataRow gt    Skip  pageNum - 1    pageSize  Take pageSize  CopyToDataTable

User · Answer

myDataTable AsEnumerable   Take 5  CopyToDataTable

User · Answer

If you want the number of rows to be flexible  you can add row number in the SQL   For SQL server    SELECT ROW NUMBER   OVER  ORDER BY myOrder  ROW NUMBER    FROM myTable  Then filter the datatable on row number   Dataview dv  new Dataview dt   ROW NUMBER lt  100       CurrentRows

[c#] How to select top n rows from a datatable/dataview in ASP.NET

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