C# Linq from DataTable

Question

I have a small DataTable that contains a number of rows which I am running a LINQ query against.

I am having problems getting the LINQ to display the text that is in the datatable.

When I run it I can get the column name.

I have tried a number of different ways of doing it but to no avail.

Code as follows:

DataTable DTGetNarratives = DAL.GetNarrativeList();

var SelectedNarrative = 
    from n in DTGetNarratives.AsEnumerable()
    where n.Field<string>("narr_code").Equals(ClsPublic.NarrativeCode)
    select n;

foreach (var item in SelectedNarrative)
{
    //test1.Add(item.Table.Columns[col].ToString());
    //col++;

    txtLine1.Text = item.Table.Columns[0].DefaultValue.ToString();
}

Any help on this would be great.

Which control do you plan to use to display? You can either set the binding straight to the "SelectedNarrative", or append(+=) to the TextBox. — Jon Douglas
– Jon Douglas, Commented Nov 25, 2013 at 16:51

Tim Schmelter · Accepted Answer · 2013-11-25 16:52:17Z

2

So you have one TextBox but an IEnumerable<DataRow>. Do you expect a single row? If not, how do you want to diplays multiple records on a single textbox?

You could comma separate them:

var allNarrCode = SelectedNarrative.Select(r => r.Field<string>("narr_code"));
txtLine1.text = string.Join(",", allNarrCode);

or as multiline TextBox use the Lines property:

txtLine1.Lines = allNarrCode.ToArray();

Only the first:

txtLine1.Text = SelectedNarrative.FirstOrDefault();

without LINQ:

foreach (DataRow row in SelectedNarrative)
{
   string code = row.Field<string>("narr_code")
   // the next line is pointless since you're overwriting the text on every row
   //txtLine1.Text = code;
}

answered Nov 25, 2013 at 16:52

Tim Schmelter

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Comments

Habib · Accepted Answer · 2013-11-25 18:09:09Z

2

You can use the Field extension method like:

foreach (var item in SelectedNarrative)
{
   txtLine1.Text = item.Field<string>("narr_code"); //here
}

(You can specify the column name in the method parameters)

I am not sure if you really need that since your TextBox would be populated with the last row's value.

To show all values in a single TextBox you can do:

txtLine1.Text = string.Join(" ",SelectedNarrative.Select(r=> r.Field<string>("narr_code")));

Or you can do

StringBuilder sb = new StringBuilder();
foreach (var item in SelectedNarrative)
{
  sb.Append(item.Field<string>("narr_code"));
}
txtLine1.Text = sb.ToString();

edited Nov 25, 2013 at 18:09

answered Nov 25, 2013 at 16:51

Habib

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1 Comment

Tim Schmelter Over a year ago

But OP has already used it in the query and you're overwriting the text always in the loop.

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