CODEWITHSUNDEEP
c#datatable
Jainendra
Jainendra

Reputation: 25143

Update two columns in a DataTable using LINQ

I want to update two columns of DataTable in a single line using LINQ query. Currently I am using following two lines to do the same:

oldSP.Select(string.Format("[itemGuid] = '{0}'", itemGuid)).ToList<DataRow>().ForEach(r => r["startdate"] = stDate);
oldSP.Select(string.Format("[itemGuid] = '{0}'", itemGuid)).ToList<DataRow>().ForEach(r => r["enddate"] = enDate);

How can I do this in one line, using one Select?

Upvotes: 13

Views: 78176

Answers (4)

user2959284
user2959284

Reputation: 59

I didn't like any of the examples I saw on the web, so here's my example

        DataTable dt = new DataTable();
        dt.Columns.Add("Year");
        dt.Columns.Add("Month");
        dt.Columns.Add("Views");
        for (int year = 2011; year < 2015; year++)
        {
            for (int month = 1; month < 13; month++)
            {
                DataRow newRow = dt.NewRow();
                newRow[0] = year;
                newRow[1] = month;
                newRow[2] = 0;
                dt.Rows.Add(newRow);
            }
        }

        dataGridView1.DataSource = dt;

        //if using Lambda 
        //var test = dt.AsEnumerable().Where(x => x.Field<string>("Year") == "2013" && x.Field<string>("Month") == "2").ToList();

        var test = (from x in dt.AsEnumerable()
                    where x.Field<string>("Year") == "2013"
                    where x.Field<string>("Month") == "2"
                    select x).ToList();


        test[0][0] = "2015";

        dt.AcceptChanges();

//if writing to sql use dt.SubmitChanges() instead

Upvotes: -1

Sergey Berezovskiy
Sergey Berezovskiy

Reputation: 236228

You can do it in one 'line', just pass appropriate action delegate to ForEach method:

oldSP.Select(string.Format("[itemGuid] = '{0}'", itemGuid))
     .ToList<DataRow>()
     .ForEach(r => { 
        r["startdate"] = stDate;
        r["enddate"] = enDate;
      });

Also you can use LINQ to DataSet (looks more readable to me, than one-liner):

var rowsToUpdate = 
    oldSP.AsEnumerable().Where(r => r.Field<string>("itemGuid") == itemGuid);

foreach(var row in rowsToUpdate)
{
    row.SetField("startdate", stDate);
    row.SetField("enddate", enDate);
}

Upvotes: 37

gzaxx
gzaxx

Reputation: 17600

Use curly bracers to do two on more operations:

oldSP.Select(string.Format("[itemGuid] = '{0}'", itemGuid))
       .ToList<DataRow>()
       .ForEach(r => { r["enddate"] = enDate); r["startdate"] = stDate; });

But for code readability I would use old-fashioned foreach loop.

Upvotes: 2

R&#233;da Mattar
R&#233;da Mattar

Reputation: 4381

Try this :

oldSP.Select(string.Format("[itemGuid] = '{0}'", itemGuid)).ToList<DataRow>()
     .ForEach(r => { r["startdate"] = stDate; r["enddate"] = enDate; });

Upvotes: 1

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