[RESOLVED] How to pass the result of the linq to textbox?

[jsc0624]

How can I pass the result of the linq to a textbox?

string search = txtSearchPO.Text;

            IPSBLL.TransactionInfo dbInfo = new IPSBLL.TransactionInfo();
            var q = from info in dbInfo.GetTransactionInfo()
                    where info.PONumber == search
                    select info;

            txtPONumber.Text = q;

I need to access the column data something like this:

DataTable.Rows[index].columnName

How can I do that in LINQ?

[danasegarane]

Try the

txtPONumber.Text = q.FirstOrDefault();

[motil]

FirstOrDefault can return null so you should check if it's null value.
also if GetTransactionInfo return an instance of a class then it should be

txtPONumber.Text = q.ProperyName.ToString();

if ProperyName is a string by default you can remove the "ToString()" part.

[gep13]

Are you expecting multiple rows to be returned from the query? If so, outputting this directly to a TextBox doesn't really make sense. It won't display the results in a usable format.

Gary

[jsc0624]

Yap I am expecting multiple rows result from the query of linq. I tried to pass it into a DataTable and here is my code:

            IPSBLL.TransactionInfo db = new IPSBLL.TransactionInfo();
            DataTable dtTransInfo = new DataTable();
            dtTransInfo = db.GetTransactionInfo();

            
            var q = from info in dtTransInfo.AsEnumerable()
                    where info.Field<string>("PONumber") == search
                    select info;
                    
            dtTransInfo = q.CopyToDataTable();

            txtPONumber.Text = dtTransInfo.Rows[0].Field<string>("PONumber");

This one works!

But unfortunately, if I will try to modify my linq query like this:

var q = from info in dtTransInfo.AsEnumerable()
                    where info.Field<string>("PONumber") == search
                    select new { 
                        TransactionInfo = info.Field<int>("TransactionInfoID"), 
                        PONumber = info.Field<string>("PONumber") 
                    };

The CopyToDataTable(); not valid anymore;

dtTransInfo = q.CopyToDataTable();

How can I fix this?

[gep13]

Hey,

I am by no means an expert on LINQ, I have been meaning to read a book on it, but just haven't got round to it.

Having said that, I think the reason that you are seeing this is due to the inferred type of q, following each query. In the first LINQ query, you are returning a number of different rows, in which case, the inferred type has the CopyToDataTable() method. However, in the second, you are no longer returning a number of different rows from the query, instead, you are returning a new instance of a class, in which case, there isn't the CopyToDataTable() method.

If you run the debugger, and set a watch on q, in both cases, you should hopefully see what I mean.

Gary

[jsc0624]

Thank you guys for the help, I have now a clear understanding...

[gep13]

Glad to hear it!

Gary