Joining Values Of Two Columns From DataTable

Question

Joining Values Of Two Columns From DataTable Two columns make it in one columns from datatable

my datatable is

   TagNumber, LogNumber  Combined
    124           1         2
    125           1         3
    126           2         4
o/p:

     TagNumber 
    124 ~1~2          
    125 ~1~3         
    126 ~2~4         
 combined column is merge from column0 and column1

i dont understand hw can i do please write sample of code

I dont have experience on linq . I add column bt hw can i merge two columns in that one columns

I got answer:

For i As Integer = 0 To dstemp.Tables(0).Rows.Count - 1
dstemp.Tables(0).Rows(i)(0) = dstemp.Tables(0).Rows(i)("TagNumber") & "~" &      dstemp.Tables(0).Rows(i)("LogNumber") & "~" & dstemp.Tables(0).Rows(i)("Combined")
next

Solution 1

Ok if you really want to do this then you have create a extra DataTable with Three Columns:

TagNumber, LogNumber Combined: as below:

private DataTable CreateDataTableColumns()
{
    DataTable dtThreeItems = new DataTable();
    dtThreeItems.Columns.Add("TagNumber", typeof(String));
    dtThreeItems.Columns.Add("LogNumber", typeof(String));
    dtThreeItems.Columns.Add("Combined", typeof(String));
    return dtThreeItems;
}

Now iterate the old datatable as below to get combined value:

foreach (DataRow dr in dtTwoItems.Rows)
            {
                row = dtThreeItems.NewRow();
                row["TagNumber"] = dr["TagNumber"].ToString();
                row["LogNumber"] = dr["LogNumber"].ToString();
                row["Combined"] = dr["TagNumber"].ToString()+"/"+dr["LogNumber"].ToString() ;
                dtThreeItems.Rows.Add(row);
            }

Thats All

Solution 2

Try doing it like this.

 dtTwoItems.Columns.Add("Combined", typeof(string), "TagNumber+'/'+LogNumber");

Solution 3

DataTable is like a container. It is not proper to join tables.

I recommend you'd use linq.

Solution 4

Did you try to Add new Column to DataTable and then iterate through Each Row to put value by combining them?

EDIT: I Am not sure if Linq or Datatable query have some inbuilt feature to do this, but simple solution is what I tell. Or if you are filling your datatable from any SQL Query based database, then write a SQL that has third column with merged value using concat of columns.

Edit2:

foreach (Datarow r in myTable.Rows) {
   r["Newcolumn"] = Convert.ToString(r["c1"]) + "/" + Convert.ToString(r["c2"]);
}

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Comments

[Harsh]

I add column bt hw can i merge two columns in that one columns

[Harsh]

I dont have experience on linq

[Harsh]

how can use dattable.merge

[Harsh]

Sumit Gupta it gives error Unable to cast object of type 'System.Data.DataTable' to type 'System.Data.DataRow'.

[Harsh]

guptaji hw can merge it in one column

[Harsh]

guptaji it gives error Unable to cast object of type 'System.Data.DataTable' to type 'System.Data.DataRow'.

[Sumit Gupta]

Not sure what you want to merge, in loop we already merge it up. It is too simple to explain.

[Harsh]

but my datatable hv not fixed columns its change according search so hw can merge in existing table

[Harsh]

wt simple guptaji try to understand my problem

[Saturn K]

This is actually the proper way of doing it. Iterating through each row is less efficient and maintainable.