DataTable customization with records

Question

I Have 1 Datatable having 10 rows and ListBox having 8 ListItems contains 6 records from the DataTable and 2 new records.

I want to update the DataTable in such a way that 6 records should be as it is and remove remaining 4 records from DataTable and add 2 newly added entries from ListBox in DataTable.

What I tried is I looped ListBox record from DataTable and created list of matched records.

string impactedTC;
List<int> index = new List<int>();
// This retruns my dataset having 10 records           
DataTable dttable = GetImpactedTestCaseDetailsToUpdateStatus().Tables[0];

for (int i = 0; i < ListBox1.Items.Count; i++)
{
    int count = 0;

    string dTestCase = ListBox1.Items[i].Text;
    foreach (DataRow dtRow in dttable.Rows)
    {
        impactedTC = dtRow["TestCaseName"].ToString();
        if (impactedTC == dTestCase)
        {
            index.Add(count);
        }
        count++;
    }
}

Please include sample code to give us something to work with. — djsoteric, Dec 30 '19 at 07:24
@djsoteric i created list of index that are matched with datatable records. now i want to remove rest of the records from datatable. — prashanat chaudhari, Dec 30 '19 at 07:33
You should be able to iterate through the records and delete them in one transaction after you've identified with rows do not belong. I would do it with LINQ instead of writing a loop though. See https://stackoverflow.com/questions/5648339/deleting-specific-rows-from-datatable — djsoteric, Dec 30 '19 at 07:41
You want to put the statement count++ inside the if statement so it only increments when you match the TestCaseName. — jdweng, Dec 30 '19 at 10:08
How can you add 2 newly added entries from list to datatable? — Selim Yildiz, Dec 30 '19 at 10:13

score 0 · Accepted Answer · 2019-12-31T11:37:22.083

0

You can do that using Ling:

To keep the 6 rows and remove the remaining 4 from the DataTable:

//Assuming the names are DataTable1 and ListBox1.
var rowsToRemove = from r in DataTable1.Rows.Cast<DataRow>()
        where listBox1.Items
        .Cast<ListItem>()
        .Aggregate(0, (n, li) => li.Text.ToLower() == r.Field<string>("TestCaseName").ToLower() ? n + 1 : n) == 0
        select r;

To get the new items from the ListBox:

var newItems = from li in listBox1.Items.Cast<ListItem>()
                where DataTable1.Rows
                .Cast<DataRow>()
                .Aggregate(0, (n, r) => r.Field<string>("TestCaseName").ToLower() == li.Text.ToLower() ? n + 1 : n) == 0
                select li;

and finally update the DataTable:

rowsToRemove.ToList().ForEach(r => DataTable1.Rows.Remove(r));
newItems.ToList().ForEach(li => DataTable1.Rows.Add(li.Text)); //or maybe li.Value

Important

You might need to replace any li.Text with li.Value in the preceding code and that depends on how the ListItem objects are created. Please check this for more details.

edited Dec 31 '19 at 11:37

answered Dec 30 '19 at 12:12

Thanks @JQSOFT I do have ListItem so struggling to to add new item into datatable. Could you please help me in this? 'System.Web.UI.WebControls.ListItem' to type 'System.IConvertible' error occurred during execution. can you help me in this. – prashanat chaudhari Dec 31 '19 at 06:14
@prashanatchaudhar Of course it will throw that exception since it is a different type. You had to make your post more clear by adding the right tags, the type of your project,.. etc. Anyway, The same logic will work if you change the types and call the correct properties. Try the edited code, – Dec 31 '19 at 09:24
@prashanatchaudhar Also check what you are really need to get, is it the [ListItem.Text](https://learn.microsoft.com/en-us/dotnet/api/system.web.ui.webcontrols.listitem.text?view=netframework-4.8#System_Web_UI_WebControls_ListItem_Text) property or the [ListItem.Value](https://learn.microsoft.com/en-us/dotnet/api/system.web.ui.webcontrols.listitem.value?view=netframework-4.8#System_Web_UI_WebControls_ListItem_Value)? – Dec 31 '19 at 09:34
ListItem.Text is required. I am new to linq i am still struggling with this. Could you please help me with the code? @JQSOFT – prashanat chaudhari Dec 31 '19 at 10:28
@prashanatchaudhar I Just did mate, check the code. I replaced the `string` with `ListItem`, and I removed the alternative function since it won't work here. Try it and tell me what you get. – Dec 31 '19 at 10:44
thanks. review view has expected values however adding into DataTable using Li.Text getting 'Input string was not in a correct format.' error and for li.value i blank values added into DataTable. – prashanat chaudhari Dec 31 '19 at 11:00
Also i want to ask rowsToRemove.ToList().ForEach(r => DataTable1.Rows.Remove(r)); rowsToRemove.ToList() i want to remove this from database using my in build function. is there any way to call my function from Linq syntax? – prashanat chaudhari Dec 31 '19 at 11:07
This is what i tried foreach(DataRow dr in rowsToRemove.ToList()) { int Count = 0; string testcase = dr.Table.Rows[Count]["TestCaseName"].ToString(); RemoveTCFromDataBase(testcase); Count++; } – prashanat chaudhari Dec 31 '19 at 11:10

DataTable customization with records

1 Answers1