How to select distinct rows in a datatable and store into an array

Question

I have a dataset objds  objds contains a table named Table1  Table1 contains column named ProcessName  This ProcessName contains repeated names So i want to select only distinct names Is this possible     intUniqId i     objds Tables 0  Rows i   ProcessName   ToString

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DataTable dtbs   new DataTable     DataView dvbs   new DataView dt    dvbs RowFilter    ColumnName  Filtervalue     dtbs   dvbs ToTable

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var ValuetoReturn    from Rows in YourDataTable AsEnumerable   select Rows  ColumnName    Distinct   ToList

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With LINQ   NET 3 5  C  3   var distinctNames     from row in DataTable AsEnumerable    select row Field lt string gt   Name    Distinct      foreach  var name in distinctNames     Console WriteLine name

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I just happened to find this  http   support microsoft com default aspx scid kb en-us 326176 1  While looking for something similar  only  specifically for  net 2 0  Im assuming the OP was looking for distinct while using DataTable Select     Select   doesn t support distinct   So here is the code from the above link   class DataTableHelper        public DataTable SelectDistinct string TableName  DataTable SourceTable  string FieldName                   DataTable dt   new DataTable TableName           dt Columns Add FieldName  SourceTable Columns FieldName  DataType            object LastValue   null           foreach  DataRow dr in SourceTable Select     FieldName                         if    LastValue    null      ColumnEqual LastValue  dr FieldName                                     LastValue   dr FieldName                    dt Rows Add new object   LastValue                                     return dt             private bool ColumnEqual object A  object B                    Compares two values to see if they are equal  Also compares DBNULL Value             Note  If your DataTable contains object fields  then you must extend this            function to handle them in a meaningful way if you intend to group on them           if   A    DBNull Value  amp  amp  B    DBNull Value       both are DBNull Value             return true           if   A    DBNull Value    B    DBNull Value       only one is DBNull Value             return false           return   A Equals B         value type standard comparison

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The most simple solution is to use LINQ and then transform the result to a DataTable         data is a DataTable that you want to change     DataTable result   data AsEnumerable   Distinct   CopyToDataTable  lt  DataRow  gt        This is valid only for asp net 4 0   Framework and it needs the reference to System Data DataSetExtensions as Ivan Ferrer Villa pointed out

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You can use like that   data is DataTable  data DefaultView ToTable true   Id    Name    Role    DC1    DC2    DC3    DC4    DC5    DC6    DC7        but performance will be down  try to use below code   data AsEnumerable   Distinct System Data DataRowComparer Default  ToList        For Performance   http   onerkaya blogspot com 2013 01 distinct-dataviewtotable-vs-linq html

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DataView view   new DataView table   DataTable distinctValues   view ToTable true   Column1    Column2

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string   TobeDistinct     Name   City   State    DataTable dtDistinct   GetDistinctRecords DTwithDuplicate  TobeDistinct      Following function will return Distinct records for Name  City and State column  public static DataTable GetDistinctRecords DataTable dt  string   Columns        DataTable dtUniqRecords   new DataTable        dtUniqRecords   dt DefaultView ToTable true  Columns       return dtUniqRecords

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objds Table1 Select r   gt  r ProcessName  AsEnumerable   Distinct

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DataTable dt   new DataTable    dt Columns Add  IntValue   typeof int    dt Columns Add  StringValue   typeof string    dt Rows Add 1   1    dt Rows Add 1   1    dt Rows Add 1   1    dt Rows Add 2   2    dt Rows Add 2   2     var x    from r in dt AsEnumerable           select r  IntValue    Distinct   ToList

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it is easy      DataView view   new DataView dt   DataTable dt2   view ToTable true   Column1    Column2   Column3        ColumnNth      and dt2 datatable contain column1 Column2  ColumnNth unique data

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sthing like    SELECT DISTINCT      FROM table WHERE condition  http   www felixgers de teaching sql sql distinct html  note  Homework question    and god bless google    http   www google com search hl en amp rlz 1C1GGLS enJO330JO333 amp q c 23 selecting distinct values from table amp aq f amp oq  amp aqi

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To improve the above answer  The ToTable function on dataview has a  distinct  flag      This will filter all records to be distinct dt   dt DefaultView ToTable true

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Following single line of code will avoid the duplicate rows of a DataTable   dataTable DefaultView ToTable true   employeeid      Where    first parameter in ToTable   is a boolean which indicates whether you want distinct rows or not  second parameter in the ToTable   is the column name based on which we have to select distinct rows  Only these columns will be in the returned datatable     The same can be done from a DataSet  by accessing a specific DataTable   dataSet Tables  Employee   DefaultView ToTable true   employeeid

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Syntax -  DataTable dt   ds Tables 0  DefaultView ToTable true   ColumnName      EX -   DataTable uniqueCols   dsUDFlable Tables 0  DefaultView ToTable true   BorrowerLabelName

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var distinctRows    from DataRow dRow in dtInventory Rows                                 select dRow  column name     Distinct     var distinctRows    from DataRow dRow in dtInventory Rows                                 select dRow  col1    dRow  col2       Distinct

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DataTable dt   new DataTable  EMPLOYEE LIST     DataColumn eeCode   dt Columns Add  EMPLOYEE CODE   typeof String    DataColumn taxYear   dt Columns Add  TAX YEAR   typeof String    DataColumn intData   dt Columns Add  INT DATA   typeof int    DataColumn textData   dt Columns Add  TEXT DATA   typeof String     dt PrimaryKey   new DataColumn     eeCode  taxYear      It filters data table with eecode and taxyear combinedly considered as unique

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Following works  I have it working for me with  NET 3 5 SP1     Create the list of columns String   szColumns   new String data Columns Count   for  int index   0  index  lt  data Columns Count  index          szColumns index    data Columns index  ColumnName        Get the distinct records data   data DefaultView ToTable true  szColumns

[c#] How to select distinct rows in a datatable and store into an array

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