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c# Randomize DataTable rows

I have a Data Table I'm using as the data source for a repeater and would like to have the results show in a random order each time it's called.
I've been able to do this while retrieving the data but wish to cache the result set before it's bound.
Is the any was to shuffle or randomise the rows of a data table before binding to the repeater?
CODE:
TreeProvider tp = new TreeProvider();
DataSet ds = new DataSet();
string sKey = "KEY";
using (CachedSection<DataSet> cs = new CachedSection<DataSet>(ref ds, 5, true, null, sKey))
{
if (cs.LoadData)
{
ds = tp.SelectNodes("", "URL", "", true, "DOCTYPE", "", "NewID()", -1, true, 5);
cs.Data = ds;
}
}
if (!DataHelper.DataSourceIsEmpty(ds))
{
rprItems.DataSource = ds.Tables[0].DefaultView;
rprItems.DataBind();
}
Any guidance is appreciated.

I ended up taking a copy of the table, adding a field and assigning a random number to each row then ordering by that row.
DataTable dt = ds.Tables[0].Copy();
if (!dt.Columns.Contains("SortBy"))
dt.Columns.Add("SortBy", typeof (Int32));
foreach (DataColumn col in dt.Columns)
col.ReadOnly = false;
Random rnd = new Random();
foreach (DataRow row in dt.Rows)
{
row["SortBy"] = rnd.Next(1, 100);
}
DataView dv = dt.DefaultView;
dv.Sort = "SortBy";
DataTable sortedDT = dv.ToTable();
rprItems.DataSource = sortedDT;
rprItems.DataBind();

You could try something like this, I know it's not pretty but:
DataTable newTable = new DataTable();
newTable.TableName = "<NewTableName>";
//Make a new Random generator
Random rnd = new Random();
while (<new table length> != <old table length>)
{
//We'll use this to make sure we don't have a duplicate row
bool rowFound = false;
//index generation
int index = rnd.Next(0, <max number of rows in old data>);
//use the index on the old table to get the random data, then put it into the new table.
foreach (DataRow row in newTable.Rows)
{
if (oldTable.Rows[index] == row)
{
//Oops, there's duplicate data already in the new table. We don't want this.
rowFound = true;
break;
}
}
if (!rowFound)
{
//add the row to newTable
newTable.Rows.Add(oldTable.Rows[index];
}
}
You'll have to use your own tables, names, and lengths of course, but this should be ok to use. If there's a lot of data, this could take a while. It's the best I can come up with, and it's untested. I'm curious to know if it works.

You could try:
DataTable dt = new DataTable();
dt.Columns.Add("Name");
dt.Columns.Add("Sort");
dt.Rows.Add("TEST");
dt.Rows.Add("TEST1");
dt.Rows.Add("TEST2");
var rnd = new Random(DateTime.Now.Millisecond);
foreach (DataRow row in dt.Rows)
{
row["Sort"] = rnd.Next(dt.Rows.Count);
}
var dv = new DataView(dt);
dv.Sort = "Sort";
foreach (DataRowView row in dv)
{
Console.WriteLine(row[0]);
}
If your datatable is not too big it should do it.

compare datatables and save unmatched rows in third datatable

I am trying to compare two datatables and capture the difference in third datatable.
DataTable one = new DataTable();
one.Columns.Add("ID");
one.Columns.Add("PCT");
one.Rows.Add("1", "0.1");
one.Rows.Add("2", "0.2");
one.Rows.Add("3", "0.3");
DataTable two = new DataTable();
two.Columns.Add("ID");
two.Columns.Add("PCT");
two.Columns.Add("OldPCT");
two.Rows.Add("1", "0.1", "0");
two.Rows.Add("2", "0.1", "0");
two.Rows.Add("3", "0.9", "0");
two.Columns.Remove("OldPCT");
//First method
DataTable three = two.AsEnumerable().Except(one.AsEnumerable()).CopyToDataTable();
foreach (DataRow dr in three.AsEnumerable())
{
string strID = dr[0].ToString();
string strPCT = dr[1].ToString();
}
//second method
var diffName = two.AsEnumerable().Select(r => r.Field<string>("PCT")).Except(one.AsEnumerable().Select(r => r.Field<string>("PCT")));
if (diffName.Any())
{
DataTable Table3 = (from row in two.AsEnumerable()
join name in diffName
on row.Field<string>("PCT") equals name
select row).CopyToDataTable();
}
So far I have tried two methods and I'm not not getting my expected result and it should be like.
In third datatable the values should be like mentioned below.
ID PCT
2 O.1
3 0.9
Recent One:
DataTable one = new DataTable();
one.Columns.Add("ID");
one.Columns.Add("PCT");
one.Rows.Add("1", "0.1");
one.Rows.Add("2", "0.2");
one.Rows.Add("2", "0.2");
one.Rows.Add("3", "0.3");
one.Rows.Add("3", "0.3");
DataTable two = new DataTable();
two.Columns.Add("ID");
two.Columns.Add("PCT");
two.Rows.Add("1", "0.1");
two.Rows.Add("2", "0.1");
two.Rows.Add("2", "0.1");
two.Rows.Add("3", "0.8");
two.Rows.Add("3", "0.9");
Now I need to get all the rows from datatable two except first row. But I am getting only last three rows.

Building on Hogan's answer, you can use DataRowComparer.Default as the second parameter to the Except() method (instead of creating a custom IEqualityComparer):
// this will get all rows from table two that don't match rows in one
// the result is an IEnumerable<DataRow>
var unmatched = two.AsEnumerable()
.Except(one.AsEnumerable(), DataRowComparer.Default);
// CopyToDataTable converts an IEnumerable<DataRow> into a DataTable
// but it blows up if the source object is empty
// this statement makes sure unmatched has data before calling CopyToDataTable()
// if it is empty, we 'clone' (make an empty copy) of one of the original DataTables
var three = unmatched.Any() ? unmatched.CopyToDataTable() : one.Clone();
This will do a value-based comparison of the fields in each row to determine if they are equal.

You need a custom IEqualityComparer
void Main()
{
DataTable one = new DataTable();
one.Columns.Add("ID");
one.Columns.Add("PCT");
one.Rows.Add("1", "0.1");
one.Rows.Add("2", "0.2");
one.Rows.Add("3", "0.3");
DataTable two = new DataTable();
two.Columns.Add("ID");
two.Columns.Add("PCT");
two.Columns.Add("OldPCT");
two.Rows.Add("1", "0.1", "0");
two.Rows.Add("2", "0.1", "0");
two.Rows.Add("3", "0.9", "0");
two.Columns.Remove("OldP
DataTable three = two.AsEnumerable().Except(one.AsEnumerable(),new RowEqualityComparer()).CopyToDataTable();
foreach (DataRow dr in three.AsEnumerable())
{
string strID = dr[0].ToString();
string strPCT = dr[1].ToString();
}
}
class RowEqualityComparer : IEqualityComparer<DataRow>
{
public bool Equals(DataRow b1, DataRow b2)
{
if ((b1.Field<string>("ID") == b2.Field<string>("ID")) && (b1.Field<string>("PCT") == b2.Field<string>("PCT")))
{
return true;
}
else
{
return false;
}
}
public int GetHashCode(DataRow bx)
{
return (bx.Field<string>("ID")+bx.Field<string>("PCT")).GetHashCode();
}
}

two datatable adding

I have two datatables.
1st table-----> DataTable _dtMain = new COrder().GetDetails();
2nd table-----> DataTable _dtSub = new CGrid().GetSubDetails();
I want to add the above two tables. I am using _dtMain.Merge(_dtSub );
But it will append _dtSub table to _dtMain table. I want datatable to add second table to first table in column wise (that means after first table last column)

Don't think there any built-in method for the thing you want to achieve.
I think you need to make your own implementation for that stuff, like for example an extension method
public static DataTable Aggregate(this DataTable dt1, DataTable dt2)
{
var aggregator = new DataTable();
//add columns from dt1 and dt2
//add rows from dt1 dt2
}
or, you can do a complete Outer Join on both tables, like descrived in this article.

After a lot of research , i find out the answer for my question that i posted before. Here is the code for combing 2 datatable & the data inside it.
public DataTable CombineTable(DataTable _dtGridDetails, DataTable _dtSubGridDetails)
{
//first create the datatable columns
DataSet mydataSet = new DataSet();
mydataSet.Tables.Add(" ");
DataTable myDataTable = mydataSet.Tables[0];
//add left table columns
DataColumn[] dcLeftTableColumns = new DataColumn[_dtGridDetails.Columns.Count];
_dtGridDetails.Columns.CopyTo(dcLeftTableColumns, 0);
foreach (DataColumn LeftTableColumn in dcLeftTableColumns)
{
if (!myDataTable.Columns.Contains(LeftTableColumn.ToString()))
myDataTable.Columns.Add(LeftTableColumn.ToString());
}
//now add right table columns
DataColumn[] dcRightTableColumns = new DataColumn[_dtSubGridDetails.Columns.Count];
_dtSubGridDetails.Columns.CopyTo(dcRightTableColumns, 0);
foreach (DataColumn RightTableColumn in dcRightTableColumns)
{
if (!myDataTable.Columns.Contains(RightTableColumn.ToString()))
{
// if (RightTableColumn.ToString() != RightPrimaryColumn)
myDataTable.Columns.Add(RightTableColumn.ToString());
}
}
//add left-table data to mytable
foreach (DataRow LeftTableDataRows in _dtGridDetails.Rows)
{
myDataTable.ImportRow(LeftTableDataRows);
}
for (int nIndex = 0; nIndex <= myDataTable.Rows.Count-1; nIndex++)
{
if (nIndex == _dtSubGridDetails.Rows.Count)
break;
myDataTable.Rows[nIndex][columnindex] = _dtSubGridDetails.Rows[nIndex][columnindex];
}
return myDataTable;
}

dataview rowfilter value to datatable convertion

I want to convert dataview rowfilter value to datatable. I have a dataset with value. Now i was filter the value using dataview. Now i want to convert dataview filter values to datatable.please help me to copy it........
My partial code is here:
DataSet5TableAdapters.sp_getallempleaveTableAdapter TA = new DataSet5TableAdapters.sp_getallempleaveTableAdapter();
DataSet5.sp_getallempleaveDataTable DS = TA.GetData();
if (DS.Rows.Count > 0)
{
DataView datavw = new DataView();
datavw = DS.DefaultView;
datavw.RowFilter = "fldempid='" + txtempid.Text + "' and fldempname='" + txtempname.Text + "'";
if (datavw.Count > 0)
{
DT = datavw.Table; // i want to copy dataview row filter value to datatable
}
}
please help me...

You can use
if (datavw.Count > 0)
{
DT = datavw.ToTable(); // This will copy dataview's RowFilterd values to datatable
}

You can use DateView.ToTable() for converting the filtered dataview in to a datatable.
DataTable DTb = new DataTable();
DTb = SortView.ToTable();

The answer does not work for my situation because I have columns with expressions. DataView.ToTable() will only copy the values, not the expressions.
First I tried this:
//clone the source table
DataTable filtered = dt.Clone();
//fill the clone with the filtered rows
foreach (DataRowView drv in dt.DefaultView)
{
filtered.Rows.Add(drv.Row.ItemArray);
}
dt = filtered;
but that solution was very slow, even for just 1000 rows.
The solution that worked for me is:
//create a DataTable from the filtered DataView
DataTable filtered = dt.DefaultView.ToTable();
//loop through the columns of the source table and copy the expression to the new table
foreach (DataColumn dc in dt.Columns)
{
if (dc.Expression != "")
{
filtered.Columns[dc.ColumnName].Expression = dc.Expression;
}
}
dt = filtered;

The below code is for Row filter from Dataview and the result converted in DataTable
itemCondView.RowFilter = "DeliveryNumber = '1001'";
dataSet = new DataSet();
dataSet.Tables.Add(itemCondView.ToTable());

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);
}