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c# split one datatable to several into dataset

I have correct source DataTable "sourceDataTable" and I call method to split it into several and store the result into DataSet "ds":
DataSet ds = MyClass.SplitDataTables(sourceDataTable);
Here is the method MyClass.SplitDataTables():
public static DataSet SplitDataTables(DataTable sourceDataTable)
{
using (DataSet dsOut = new DataSet())
{
DataTable dt1 = new DataTable;
DataTable dt2 = new DataTable;
DataTable dt3 = new DataTable;
dt1 = sourceDataTable.Clone();
dt2 = sourceDataTable.Clone();
dt3 = sourceDataTable.Clone();
foreach (DataRow row in sourceDataTable.Rows)
{
//column is for example "City" and some row has "Boston" in it, so I put this row into dt1
if (row["ColumnName"].ToString() == "something")
{
dt1.ImportRow(row);
}
else if (...)
{ } //for other DataTables dt2, dt3, etc...
else .......... ;
}
//here I put resulting DataTables into one DataSet which is returned
string[] cols= { "dt1", "dt2", "dt3" };
foreach (string col in cols)
{
dsOut.Tables.Add(col);
}
return dsOut;
}
}
So with this returned DataSet I display new Windows each with one DataTable
foreach (DataTable dtt in ds.Tables)
{
string msg = dtt.TableName;
Window2 win2 = new Window2(dtt, msg);
win2.Show();
}
All I get shown is Windows with placeholder for "empty DataGrid"
Windows code is correct, as it works whith "unsplit DataTable".
I assume code in splitting DataTables is all wrong as it does not output DataSet with filled DataTables. I will greatly appreciate any help on this issue. Thank you!

You don't need a for loop here
Replace below code
string[] cols= { "dt1", "dt2", "dt3" };
foreach (string col in cols)
{
dsOut.Tables.Add(col);
}
With this
dsOut.Tables.Add(dt1);
dsOut.Tables.Add(dt2);
dsOut.Tables.Add(dt3);

Thanks to #Krishna I got this solved. So if you ever encounter similar problem here are 2 things to note:
string[] cols = { "dt1", "dt2", "dt3", ... };
foreach (string col in cols)
{
dsOut.Tables.Add(col);
}
This cycle does not have access to objects of DataTables with same name and writes only empty DataTables into DataSet collection (regardless of same name!).
If you create new DataTable and you will be making it a clone of another DataTable, dont bother yet with setting its name.
DataTable dt1 = new DataTable();
Make new DataTable of same format as source DataTable:
dt1 = sourceDataTable.Clone();
dt2 = sourceDataTable.Clone();
//etc...
Now you have to set unique DataTable names to each DataTable cloned from source DataTable:
dt1.TableName = "Name1";
dt2.TableName = "Name2";
//and so on
Now all works as intended.

DataTable Select not returning values

I have a datatable and I'm trying to select some of the rows from the datatable.
It works well for PracticeIDs 1 & 37, but for some reason, when it gets to the last row of the data(ID 7), it doesn't pull up the record from the datatable.
Any ideas?
//create datatable
DataTable dt = new DataTable();
dt.Columns.Add("PracticeID");
dt.Columns.Add("AuthorID");
//add data(in real code, this is pulled from the database)
dt.Rows.Add(1, 87);
dt.Rows.Add(37, 202);
dt.Rows.Add(1, 268);
dt.Rows.Add(7, 262);
//get distinct practiceids into datatable
DataView dv = new DataView(dt);
DataTable dtDistinctIDs = dv.ToTable(true, "PracticeID");
//for each practice, get a list of the authors
foreach (DataRow practiceRow in dtDistinctIDs.Rows)
{
DataRow[] dra = dt.Select("PracticeID = " + practiceRow["PracticeID"].ToString());
}

This was hard to spot, as this behaviour seems counterintuitive. The problem you are experimenting is derived of the columns not having a datatype. I now can't explain it exactly, but try to change your code to the following and it would work as expected:
DataTable dt = new DataTable();
dt.Columns.Add("PracticeID",typeof(int)); //THIS IS THE IMPORTANT BIT
dt.Columns.Add("AuthorID");
//add data(in real code, this is pulled from the database)
dt.Rows.Add(1, 87);
dt.Rows.Add(37, 202);
dt.Rows.Add(1, 268);
dt.Rows.Add(7, 262);
//get distinct practiceids into datatable
DataView dv = new DataView(dt);
DataTable dtDistinctIDs = dv.ToTable(true, "PracticeID");
//for each practice, get a list of the authors
foreach (DataRow practiceRow in dtDistinctIDs.Rows)
{
DataRow[] dra = dt.Select("PracticeID = " + (int)practiceRow["PracticeID"]);
}
EDIT:
In fact I was wrong and it was simpler. The real problem was with your Select not having ' surrounding the field, as by default the DataColumn is string. So, using your original code, just changing the following should work:
DataRow[] dra = dt.Select("PracticeID = '" + practiceRow["PracticeID"].ToString() + "'");

filter a data table with values from an array c#

I have a delete method, it gets an array of GUIDs and I have a data table... how can I filter the data table so it will only contain thoes GUIDs?
public void delete(Guid[] guidlist)
{
datatable template = ReadTemplateList()
...
}
Thank you!

With Linq to DataSet you can create new DataTable which will have only rows with those Guids:
public void Delete(Guid[] guids)
{
DataTable table = ReadTemplateList()
.AsEnumerable()
.Where(r => guids.Contains(r.Field<Guid>("ColumnName")))
.CopyToDataTable();
// ...
}
Another option (which also will work on old .NET versions) is filtering your table with built-in RowFilter functionality which supports IN filters. Let's assume you are filtering by column named ID:
// Check if guids.Length > 0
StringBuilder filter = new StringBuilder("ID IN (");
foreach (Guid id in guids)
filter.AppendFormat("Convert('{0}','System.Guid'),", id);
filter.Append(")");
DataTable template = ReadTemplateList();
DataView view = template.DefaultView;
view.RowFilter = filter.ToString();
DataTable table = view.ToTable();

You can use LINQ:
public static DataTable DeleteGuidsFromTemplate(Guid[] guidlist)
{
DataTable template = ReadTemplateList();
var rowsWithGuids = from row in template.AsEnumerable()
join guid in guidlist
on row.Field<Guid>("Guid") equals guid
select row;
return rowsWithGuids.CopyToDataTable();
}
If you can't use LINQ since you're lower than NET 3.5:
public static DataTable DeleteGuidsFromTemplate(Guid[] guidlist)
{
DataTable template = ReadTemplateList();
DataTable templateGuids = template.Clone();
foreach(DataRow row in template.Rows)
{
Guid guid = (Guid)row["Guid"];
int index = Array.IndexOf(guidlist, guid);
if (index >= 0)
templateGuids.ImportRow(row);
}
return templateGuids;
}

A solution based on DataTable and DataRows.
//fill the datatable from back end
string connStr = ConfigurationManager.ConnectionStrings["ConsoleApplication1.Properties.Settings.NORTHWNDConnectionString"].ConnectionString;
SqlConnection conn = new SqlConnection(connStr);
conn.Open();
SqlCommand comm = new SqlCommand("select categoryid,categoryname from Categories order by categoryname");
comm.Connection = conn;
SqlDataReader dr = comm.ExecuteReader();
DataTable dt = new DataTable();
dt.Load(dr);
//datatable filter logic
string[] filter = { "1", "2" };
DataTable filteredTable = dt.Clone();
foreach (string str in filter)
{
DataRow[] filteredRows = dt.Select("categoryid="+ str); //search for categoryID
foreach (DataRow dtr in filteredRows)
{
filteredTable.ImportRow(dtr);
}
}
EDIT
Without going in the for loop
DataTable dt = new DataTable();
dt.Load(dr); //fill the datatable with sqldatareader
DataTable filteredTable = dt.Clone();
DataView dv = dt.DefaultView;
dv.RowFilter = "categoryid in (1,2)";
filteredTable = dv.ToTable();

Sorting rows in a data table

We have two columns in a DataTable, like so:
COL1 COL2
Abc 5
Def 8
Ghi 3
We're trying to sort this datatable based on COL2 in decreasing order.
COL1 COL2
ghi 8
abc 4
def 3
jkl 1
We tried this:
ft.DefaultView.Sort = "COL2 desc";
ft = ft.DefaultView.ToTable(true);
but, without using a DataView, we want to sort the DataTable itself, not the DataView.

I'm afraid you can't easily do an in-place sort of a DataTable like it sounds like you want to do.
What you can do is create a new DataTable from a DataView that you create from your original DataTable. Apply whatever sorts and/or filters you want on the DataView and then create a new DataTable from the DataView using the DataView.ToTable method:
DataView dv = ft.DefaultView;
dv.Sort = "occr desc";
DataTable sortedDT = dv.ToTable();

This will help you...
DataTable dt = new DataTable();
dt.DefaultView.Sort = "Column_name desc";
dt = dt.DefaultView.ToTable();

Its Simple Use .Select function.
DataRow[] foundRows=table.Select("Date = '1/31/1979' or OrderID = 2", "CompanyName ASC");
DataTable dt = foundRows.CopyToDataTable();
And it's done......Happy Coding

Maybe the following can help:
DataRow[] dataRows = table.Select().OrderBy(u => u["EmailId"]).ToArray();
Here, you can use other Lambda expression queries too.

Or, if you can use a DataGridView, you could just call Sort(column, direction):
namespace Sorter
{
using System;
using System.ComponentModel;
using System.Windows.Forms;
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
this.dataGridView1.Rows.Add("Abc", 5);
this.dataGridView1.Rows.Add("Def", 8);
this.dataGridView1.Rows.Add("Ghi", 3);
this.dataGridView1.Sort(this.dataGridView1.Columns[1],
ListSortDirection.Ascending);
}
}
}
Which would give you the desired result:

Did you try using the Select(filterExpression, sortOrder) method on DataTable? See here for an example. Note this method will not sort the data table in place, if that is what you are looking for, but it will return a sorted array of rows without using a data view.

table.DefaultView.Sort = "[occr] DESC";

Use LINQ - The beauty of C#
DataTable newDataTable = baseTable.AsEnumerable()
.OrderBy(r=> r.Field<int>("ColumnName"))
.CopyToDataTable();

There is 2 way for sort data
1) sorting just data and fill into grid:
DataGridView datagridview1 = new DataGridView(); // for show data
DataTable dt1 = new DataTable(); // have data
DataTable dt2 = new DataTable(); // temp data table
DataRow[] dra = dt1.Select("", "ID DESC");
if (dra.Length > 0)
dt2 = dra.CopyToDataTable();
datagridview1.DataSource = dt2;
2) sort default view that is like of sort with grid column header:
DataGridView datagridview1 = new DataGridView(); // for show data
DataTable dt1 = new DataTable(); // have data
dt1.DefaultView.Sort = "ID DESC";
datagridview1.DataSource = dt1;

It turns out there is a special case where this can be achieved. The trick is when building the DataTable, collect all the rows in a list, sort them, then add them. This case just came up here.

//Hope This will help you..
DataTable table = new DataTable();
//DataRow[] rowArray = dataTable.Select();
table = dataTable.Clone();
for (int i = dataTable.Rows.Count - 1; i >= 0; i--)
{
table.ImportRow(dataTable.Rows[i]);
}
return table;

TL;DR
use tableObject.Select(queryExpression, sortOrderExpression) to select data in sorted manner
Complete example
Complete working example - can be tested in a console application:
using System;
using System.Data;
namespace A
{
class Program
{
static void Main(string[] args)
{
DataTable table = new DataTable("Orders");
table.Columns.Add("OrderID", typeof(Int32));
table.Columns.Add("OrderQuantity", typeof(Int32));
table.Columns.Add("CompanyName", typeof(string));
table.Columns.Add("Date", typeof(DateTime));
DataRow newRow = table.NewRow();
newRow["OrderID"] = 1;
newRow["OrderQuantity"] = 3;
newRow["CompanyName"] = "NewCompanyName";
newRow["Date"] = "1979, 1, 31";
// Add the row to the rows collection.
table.Rows.Add(newRow);
DataRow newRow2 = table.NewRow();
newRow2["OrderID"] = 2;
newRow2["OrderQuantity"] = 2;
newRow2["CompanyName"] = "NewCompanyName1";
table.Rows.Add(newRow2);
DataRow newRow3 = table.NewRow();
newRow3["OrderID"] = 3;
newRow3["OrderQuantity"] = 2;
newRow3["CompanyName"] = "NewCompanyName2";
table.Rows.Add(newRow3);
DataRow[] foundRows;
Console.WriteLine("Original table's CompanyNames");
Console.WriteLine("************************************");
foundRows = table.Select();
// Print column 0 of each returned row.
for (int i = 0; i < foundRows.Length; i++)
Console.WriteLine(foundRows[i][2]);
// Presuming the DataTable has a column named Date.
string expression = "Date = '1/31/1979' or OrderID = 2";
// string expression = "OrderQuantity = 2 and OrderID = 2";
// Sort descending by column named CompanyName.
string sortOrder = "CompanyName ASC";
Console.WriteLine("\nCompanyNames data for Date = '1/31/1979' or OrderID = 2, sorted CompanyName ASC");
Console.WriteLine("************************************");
// Use the Select method to find all rows matching the filter.
foundRows = table.Select(expression, sortOrder);
// Print column 0 of each returned row.
for (int i = 0; i < foundRows.Length; i++)
Console.WriteLine(foundRows[i][2]);
Console.ReadKey();
}
}
}
Output

try this:
DataTable DT = new DataTable();
DataTable sortedDT = DT;
sortedDT.Clear();
foreach (DataRow row in DT.Select("", "DiffTotal desc"))
{
sortedDT.NewRow();
sortedDT.Rows.Add(row);
}
DT = sortedDT;

Yes the above answers describing the corect way to sort datatable
DataView dv = ft.DefaultView;
dv.Sort = "occr desc";
DataTable sortedDT = dv.ToTable();
But in addition to this, to select particular row in it you can use LINQ and try following
var Temp = MyDataSet.Tables[0].AsEnumerable().Take(1).CopyToDataTable();

Simple way to convert datarow array to datatable

I want to convert a DataRow array into DataTable ... What is the simplest way to do this?

For .Net Framework 3.5+
DataTable dt = new DataTable();
DataRow[] dr = dt.Select("Your string");
DataTable dt1 = dr.CopyToDataTable();
But if there is no rows in the array, it can cause the errors such as The source contains no DataRows. Therefore, if you decide to use this method CopyToDataTable(), you should check the array to know it has datarows or not.
if (dr.Length > 0)
DataTable dt1 = dr.CopyToDataTable();
Reference available at MSDN:
DataTableExtensions.CopyToDataTable Method (IEnumerable)

Why not iterate through your DataRow array and add (using DataRow.ImportRow, if necessary, to get a copy of the DataRow), something like:
foreach (DataRow row in rowArray) {
dataTable.ImportRow(row);
}
Make sure your dataTable has the same schema as the DataRows in your DataRow array.

DataTable dt = new DataTable();
DataRow[] dr = (DataTable)dsData.Tables[0].Select("Some Criteria");
dt.Rows.Add(dr);

Another way is to use a DataView
// Create a DataTable
DataTable table = new DataTable()
...
// Filter and Sort expressions
string expression = "[Birth Year] >= 1983";
string sortOrder = "[Birth Year] ASC";
// Create a DataView using the table as its source and the filter and sort expressions
DataView dv = new DataView(table, expression, sortOrder, DataViewRowState.CurrentRows);
// Convert the DataView to a DataTable
DataTable new_table = dv.ToTable("NewTableName");

Simple way is:
// dtData is DataTable that contain data
DataTable dt = dtData.Select("Condition=1").CopyToDataTable();
// or existing typed DataTable dt
dt.Merge(dtData.Select("Condition=1").CopyToDataTable());

DataTable Assetdaterow =
(
from s in dtResourceTable.AsEnumerable()
where s.Field<DateTime>("Date") == Convert.ToDateTime(AssetDate)
select s
).CopyToDataTable();

DataTable dt = myDataRowCollection.CopyToDataTable<DataRow>();

DataTable dt = new DataTable();
foreach (DataRow dr in drResults)
{
dt.ImportRow(dr);
}

.Net 3.5+ added DataTableExtensions, use DataTableExtensions.CopyToDataTable Method
For datarow array just use .CopyToDataTable() and it will return datatable.
For single datarow use
new DataRow[] { myDataRow }.CopyToDataTable()

You could use System.Linq like this:
if (dataRows != null && dataRows.Length > 0)
{
dataTable = dataRows.AsEnumerable().CopyToDataTable();
}

Here is the solution. It should work fine.
DataTable dt = new DataTable();
dt = dsData.Tables[0].Clone();
DataRows[] drResults = dsData.Tables[0].Select("ColName = 'criteria');
foreach(DataRow dr in drResults)
{
object[] row = dr.ItemArray;
dt.Rows.Add(row);
}

Incase anyone needs it in VB.NET:
Dim dataRow as DataRow
Dim yourNewDataTable as new datatable
For Each dataRow In yourArray
yourNewDataTable.ImportRow(dataRow)
Next

You need to clone the structure of Data table first then import rows using for loop
DataTable dataTable =dtExisting.Clone();
foreach (DataRow row in rowArray) {
dataTable.ImportRow(row);
}

DataTable dataTable = new DataTable();
dataTable = OldDataTable.Tables[0].Clone();
foreach(DataRow dr in RowData.Tables[0].Rows)
{
DataRow AddNewRow = dataTable.AddNewRow();
AddNewRow.ItemArray = dr.ItemArray;
dataTable.Rows.Add(AddNewRow);
}