Develop Reference

Add columns into a DataTable inside a loop

I'd like to know if there is a way to automatically add columns in a DataTable inside a foreach loop? That is what I mean with "automatically".
I had in mind something like this:
DataTable dt = new DataTable();
foreach (var item in model.Statistik)
{
dt.Columns.Add();
row = dt.NewRow();
row[//Name of column goes here] = // either item or item.property;
dt.Rows.Add(row);
}
This is much more efficient than explicitly name every column before the for each loop. Because, what happens if some property changes or gets deleted, etc.? This is therefore, something I wish to get rid of.

I don't think you understand how dt.Columns and dt.Rows are related. There is one set of Columns for a DataTable. Every Row in the DataTable has all the matching columns - you don't have unique Columns in each Row. So every time you do dt.Columns.Add you are adding a column to every Row, old or new.
Also, how do you expect Row[<name of column>] to work if you don't specify the name to the DataTable?

adding a column to a specific row in dataset

I have a dataset.
I want to iterate it and add a column (currently not in my dataset) with different value to every row. More specificly, i want it to be at 0 index.
I want to check the value in "fullname" column, and then add a new column with Id.
What do i need to write?
I iterate like this:
foreach (DataRow theRow in mesakem.Tables["fullname"].Rows)
foreach(oved o in ovdimlist)
if(o.name==theRow.ToString())
add column(o.id)......
Ty very much!

I think you meant to insert a new column at index 0 and then add id values to cell for each row where current name cell value matches your object name. If I'm right, it should look like this:
DataColumn col = mesakem.Tables["fullname"].Columns.Add("Id");
col.SetOrdinal(0);
foreach (DataRow row in mesakem.Tables["fullname"].Rows)
{
foreach (oved o in ovdimlist)
{
if (o.name == row["Name"].ToString())
row["Id"] = o.id;
}
}

i want to pass value from another datatable

I am having one datatable to that table i want to pass value from another datatable.
for example:-
datatable1 in this
i want to pass value from
datatable2.row[0]["colname"]
i tried like :-
tblvdr.Rows[0]["item_Vendorname"] = dttemp.Rows[0]["item_Vendorname"];
error message:-
its showing error for No row at o position

DataRow tblvdrRow = tblvdr.NewRow();
tblvdrRow["item_Vendorname"]= dttemp.Rows[0]["item_Vendorname"];
tblvdr.Rows.Add(tblvdrRow);

It looks like your data table tblvrd does not have any row. For this use
DataRow newRow = tblvdr.NewRow();
One tme a new row is generated you can populate it from the row in another table. Naturally you need generate new row in tblvdr for every row in dttemp

How to make column names the first row?

I have a query using dynamic pivot, so the column names change based on the data. My code generates a .csv file based on the result of the query. I don't know how I can make the header, as I cannot hard-code column names. Is it possible somehow to make the header of the query result the first row of the recordset?
Thanks.
ADDED: Just realized that I don't even know how to fetch the data in my C# code if I don't know what columns I have... So that I cannot do something like this:
result.AddRange(from DataRow dr in dt.Rows
select new DailyTransactionSheet
{
Serve = Convert.ToInt32(dr["Serve"]),
Remits = Convert.ToInt32(dr["Remits"]),
List = Convert.ToInt32(dr["List"]),
Billing = Convert.ToInt32(dr["Billing"]),
DollarSent = Convert.ToInt32(dr["DollarSent"]),
FileAck = Convert.ToInt32(dr["FileAck"]),
});
}

as per comments:
basically you need to execute query and fetch information about columns form it, depending on how your're executing it, there can be several options:
SQLDataReader to fetch results, you can get column information from GetSchemaTable.Columns GetSchemaTable
or
SqlDataAdapter.Fill(DataSet) DataSet.Tables[0].Columns - these methods and properties you should read about DataSet.Tables
here is example from msdn:
private void PrintRows(DataSet dataSet)
{
// For each table in the DataSet, print the row values.
foreach(DataTable table in dataSet.Tables)
{
foreach(DataRow row in table.Rows)
{
foreach (DataColumn column in table.Columns)
{
Console.WriteLine(row[column]);
}
}
}
}

C# getting values from DataTable or BindingSource

I have a labels that need values retreieved from a Database.
I am able to query the database but how can I extract values from a DataTable and place them in the appropiate labels
Thanks

In DataTable you have rows and columns. To select a particular cell you need to do this:
label1.Text = dataTable[0][0];
This will set the label1 text to Row 0, Column 0 value.
To iterate through each row use:
foreach(DataRow row in dataTable.Rows)
{
Console.WriteLine(row["ColumnName1"]);
Console.WriteLine(row["ColumnName2"]);
Console.WriteLine(row["ColumnName3"]);
Console.WriteLine(row["ColumnName4"]);
}
This will print values for columns against each row. In this code you need to replace string for columnname (e.g. ColumnName1) with your column names

Example of how you retrieve a value from the first row and the column named "MyFirstColumn":
label1.Text = myDataTable.Rows[0]["MyFirstColumn"]