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c# How to build a custom DataView from a DataTable?

I need to create a DataView from a DataTable, but with an unusual twist:
I need to decide (with code) on a row-by-row basis which rows in the DataTable are included in the DataView.
DataTable dt = LoadData();
DataView dv = new DataView(dt);
foreach (DataRow row in dt.Rows)
{
if (RowIsGood(row))
{
// This obviously doesn't work but I need equivalent logic:
DataRowView drv = new DataRowView();
drv.Row = row;
dv.Add(drv);
}
}
Some important things to note:
The code in the RowIsGood function above is too complicated to replicate using the standard RowFilter method.
The DataTable has the potential to be very large. It is also referenced by multiple grid controls. Adding temporary columns to the DataTable to facilitate a RowFilter operation is not possible.
I'm using .NET v4.0.
Is then even possible with the DataTable/DataView architecture?
Does LINQ allow me to customize a DataView like I need?
Thanks in advance!

Since you are looking for a row by row solution and already have a function that takes a DataRow and returns a bool.
Simply add the refernce to System.Data.DataSetExtensions
And use the AsDataView Method
DataView dv=DT.AsEnumerable().Where(RowIsGood).AsDataView();

DataView dv = (from n in DT.AsEnumerable() Where RowIsGood(n) select n ).AsDataView();

How to get particular DataTable using TableName?

One DataSet usually has lots of DataTable, but I'm only to target a particular DataTable which I thought it's pretty normal but apparently failed to do it?
Below were the approaches I've tried:
//Could not find an implementation of the query pattern for source type.......
DataTable dt = from table in changesDataSet.Tables
where table.TableName = "ABC"
select table;
//Surprisingly there was no method "Where" in changesDataSet.Tables
DataTable dt = changesDataSet.Tables.Where(x=>x.TableName="ABC").First();
Below was the code that able to print each and every table. I know I can do it via a loop but please tell me loop isn't the only options
foreach(DataTable table in changesDataSet.Tables)
{
Console.WriteLine(table.TableName);
}

You can access the table using an indexer on the collection of tables (DataTableCollection):
DataTable dt = changesDataSet.Tables["ABC"];

How to access records after using RowFilter on DataGridView?

I have a DataGridView which I have used RowFilter on it like following:
(dgv.DataSource as DataTable).DefaultView.RowFilter = whereClause;
Before applying the RowFilter the DataGridView has 1087 records and afterwards, it has about 8.
Now I want to work on those 8 records.
How can I access them?

If you do
dgv.DataSource as DataTable
Then you can do the following
dataTable dt = dgv.DataSource as DataTable;
DataRow[] rows = dt.Select("your filter goes here");
You can do same thing by Linq if you want to. These are your rows and you can work with them. And to Edit only these records do:
DataGridView.DataSource = rows;
Also, you can create a custom DataView, which will filter records the way you want it, and set datasource to that view. But remember, the key here, no matter how many views you have - this is same dataTable that you looking at
DataView view = new DataView();
view.Table = dt;
view.RowFilter = "your filter";
view.Sort = "your sort";

You can use DataGridViewRow.DataBoundItem to access to the underlying data.
If your DataGridView bound to the DataView the underlying data is of type DataRowView. You can use code like this:
var dataRow = dgv.Rows[rowIndex].DataBoundItem as DataRowView;

How to assign Sorted DataView to DataTable with keeping Sorted State using C#?

I have a DataView with Sort applied on it. I am not able to assign/copy the Sorted State of DataView to DataTable.
Sort the DataView with Column 'Distance':
DataTable table=GetData();
DataView view = table.DefaultView;
view.Sort = "Distance";
this works fine.
But, when i assign this DataView to DataTable it *LOOSES THE SORTED STATE*.
DataTable dt = (view.Table);
This looses the Sorted State of DataView
Any idea?
Please correct my code if something wrong.
So, i want to assign/copy the Sorted DataView to DataTable without loosing the Sorted State.

Use view.ToTable() instead of view.Table. Please see below snippet
DataTable table=GetData();
DataView view = table.DefaultView;
view.Sort = "Distance";
DataTable dt = view.ToTable();

You can directly get dataview propery in the Datatable itself.
DataTable table=GetData();
table.DefaultView.Sort="Distance";
table=table.DefaultView.ToTable();

Here's a really efficient way to write a one line sort that maintains the sorting of the DataView in the parent DataTable.
table = new DataView(table, "", "Distance",
DataViewRowState.CurrentRows).ToTable()

DataTable merge and sort

I have two DataTables that have the same columns. I would like to append one of these DataTables on to the end of the other and then sort them by date. What is the best way of going about this?
When I try to merge and sort them, like this:
private DataTable mergeAndSortTables(DataTable manualTable, DataTable gpsTable)
{
manualTable.Merge(gpsTable);
manualTable.DefaultView.Sort = "Date DESC";
return manualTable.DefaultView.ToTable();
}
I still end up with rows out of order. What am I doing wrong?
Edit: I also get the exact same results with this code:
private DataTable mergeAndSortTables(DataTable manualTable, DataTable gpsTable)
{
manualTable.Merge(gpsTable);
DataView view = manualTable.DefaultView;
view.Sort = "Date DESC";
return view.ToTable();
}

Instead of modifying the default view, create a new view based upon the current table an sort that. This should fix your issue.

You have to assigne the dataview and then work on it.
DefaultView view = manualTable.DefaultView;
view.Sort = "Date DESC";
return view.ToTable();

I think the problem might be that Date is a keyword - try ...
manualTable.DefaultView.Sort = "[Date] DESC";

You can use DataTable.Select() method for sorting although it will return you the DataRow[]. For example, after merging, you can do DataRow[] rows = manualTable.Select("", columnName sortOrder). You can always convert this DataRow[] to another table and return it.