ASP.NET - Difference Between Lists OF Columns

Riddhi Valecha

5y759.NET

Hello Team,

I have a multi-select listbox.

It has all the column values of a table.

I have a datatable with 107 columns.

Now, from the user-interface, user has to select the columns that the user wants to see in the gridview.

How do I - remove the columns from datatable which the user does not want.?

From listbox items, how do I subtract datatable columns?

Please guide.

4 Replies

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Sachin Singh5y ago
Accepted answer
there are multiple ways at least 4 ways that I have used, among all the below code seems easiest.

step 1. you have a ListBox with mode set to multiple as
"ddlstatus" runat="server" AutoPostBack="false" AppendDataBoundItems="true" SelectionMode="Multiple">
step 2. From the above selection create one array as
var selectedColumns = ddlstatus.Items.Cast()
                         .Where(i => i.Selected)
                         .Select(i => i.Value)
                         .ToArray();
step 3 Easily filter the datatable as
DataTable dt= new DataView(oldDataTable).ToTable(false, selectedColumns);
And that's it. Easy.
+2
Jignesh Kumar5y ago
Hi,

Please refer this linkw which will help you,

https://stackoverflow.com/questions/14497367/how-i-can-search-rows-in-a-datatable-with-a-searchstring

You can pass selected columns list and select that's columns from. Data table
+1
Riddhi Valecha5y ago
Hello Sir,
I have seen both the links, but they did not work for me.

My Requirement is -
1. I have a listbox with column values
Name
Age
Address
City
State
Category
Department

2. THis is a multi-select listbox.
3. Now, when user selected only few column names - Name, State, Category
4. Then User will click on "Show Data" button
5. Then, in the gridview, only these three columbs - Name, State, Category should be displayed, not all.
How do I do this ?
+1
Jignesh Kumar5y ago
Hi Ridhi,

You can query data table and create new datatable using selecting specific column,

Please refer this link which will help you,
https://www.c-sharpcorner.com/blogs/how-to-get-a-particular-datacolumn-values-from-datatable-using-linq-in-c-sharp1
https://www.aspsnippets.com/Articles/SELECT-specific-columns-from-DataTable-using-LINQ-in-C-and-VBNet.aspx
+1