How do I create a DataTable, then add rows to it?

I've tried creating a `DataTable` and adding rows to it like this:

DataTable dt = new DataTable();
dt.clear();
dt.Columns.Add("Name");
dt.Columns.Add("Marks");

How do I see the structure of `DataTable`?

Now I want to add *ravi* for `Name` and *500* for `Marks`. How can I do this?

To add a row:

DataRow row = dt.NewRow();
row["Name"] = "Ravi";
row["Marks"] = 500;
dt.Rows.Add(row);

To see the structure:

Table.Columns

You have to add datarows to your datatable for this.

// Creates a new DataRow with the same schema as the table.
DataRow dr = dt.NewRow();

// Fill the values
dr["Name"] = "Name";
dr["Marks"] = "Marks";

// Add the row to the rows collection
dt.Rows.Add ( dr );

In addition to the other answers.

If you control the structure of the DataTable there is a shortcut for adding rows:

// Assume you have a data table defined as in your example named dt
dt.Rows.Add("Name", "Marks");

The DataRowCollection.Add() method has an overload that takes a param array of objects. This method lets you pass as many values as needed, but they must be in the same order as the columns are defined in the table.

So while this is a convenient way to add row data, it can be risky to use. If the table structure changes your code will fail.

You can also pass in an object array as well, like so:

DataTable dt = new DataTable();
dt.Clear();
dt.Columns.Add("Name");
dt.Columns.Add("Marks");
object[] o = { "Ravi", 500 };
dt.Rows.Add(o);

Or even:

dt.Rows.Add(new object[] { "Ravi", 500 });

DataTable dt=new DataTable();
Datacolumn Name = new DataColumn("Name");
Name.DataType= typeoff(string);
Name.AllowDBNull=false; //set as null or not the default is true i.e null
Name.MaxLength=20; //sets the length the default is -1 which is max(no limit)
dt.Columns.Add(Name);
Datacolumn Age = new DataColumn("Age", typeoff(int));`

dt.Columns.Add(Age);

DataRow dr=dt.NewRow();

dr["Name"]="Mohammad Adem"; // or dr[0]="Mohammad Adem";
dr["Age"]=33; // or dr[1]=33;
dt.add.rows(dr);
dr=dt.NewRow();

dr["Name"]="Zahara"; // or dr[0]="Zahara";
dr["Age"]=22; // or dr[1]=22;
dt.rows.add(dr);
Gv.DataSource=dt;
Gv.DataBind();