Adding new Row problem

[modernthinker]

Can anybody see why this add new row isn't working?

		public void dg_Insert(Object s, DataGridCommandEventArgs e) 
		{	
			if (e.CommandName == "Insert")
			{
				DataSet ds = new DataSet();
				ds.ReadXml(Server.MapPath("wineList.xml"));

				DataTable dt = new DataTable("wines");
				DataRow dr;

				dt = ds.Tables["wines"];
			
				// add new wine 
				dr = dt.NewRow();
				dr["name"] = ((TextBox)e.Item.FindControl("txtNewName")).Text;
				dr["coo"] = ((TextBox)e.Item.FindControl("txtNewCoo")).Text;
				dr["BT"] = ((TextBox)e.Item.FindControl("txtNewBT")).Text;
				dr["ml"] = ((TextBox)e.Item.FindControl("txtNewMl")).Text;
				dr["type"] = ((TextBox)e.Item.FindControl("txtNewType")).Text;
				dr["id"] = GetNextNodeID() + 1;
				dt.Rows.Add(dr);


				DataGridWine.DataSource = ds.Tables["wines"];
				DataGridWine.DataBind();

				ds.WriteXml(Server.MapPath("wineList.xml"));


			}

		}

I get an error at this line: dt.Rows.Add(dr);

System.NullReferenceException: Object reference not set to an instance of an object.

[VBKNIGHT]

you have to set intance of dr. this is the datarow right? i dont kno c# but it has somthing to do with something like this: DataRow dr = new datarow();

[modernthinker]

Hi,

I have tried using Data dr = new DataRow();

This still doesn't work.

[VBKNIGHT]

this one works for me i dont kno how to translate to c#

Dim ds As New DataSet
        Dim dt As New DataTable
        Dim dr As DataRow

        ds.ReadXml(Server.MapPath("xml\wineList.xml"))
        dt = New DataTable("wines")
        dt = ds.Tables("wines")

        ' add new wine 
        dr = dt.NewRow()
        dr("name") = TextBox1.Text
        dr("coo") = TextBox2.Text
        dr("BT") = TextBox3.Text
        dr("ml") = TextBox4.Text
        dr("type") = TextBox5.Text
        dr("id") = 1
        dt.Rows.Add(dr)


        DataGrid1.DataSource = ds.Tables("wines")
        DataGrid1.DataBind()

[wild_bill]

Couldn't you get rid of the dt variable all together?
Something like this:

		public void dg_Insert(Object s, DataGridCommandEventArgs e) 
		{	
			if (e.CommandName == "Insert")
			{
				DataSet ds = new DataSet();
				ds.ReadXml(Server.MapPath("wineList.xml"));

				DataRow dr;

				// add new wine 
				dr = ds.Tables("wines").NewRow();
				dr["name"] = ((TextBox)e.Item.FindControl("txtNewName")).Text;
				dr["coo"] = ((TextBox)e.Item.FindControl("txtNewCoo")).Text;
				dr["BT"] = ((TextBox)e.Item.FindControl("txtNewBT")).Text;
				dr["ml"] = ((TextBox)e.Item.FindControl("txtNewMl")).Text;
				dr["type"] = ((TextBox)e.Item.FindControl("txtNewType")).Text;
				dr["id"] = GetNextNodeID() + 1;
				ds.Tables("wines").Rows.Add(dr);


				DataGridWine.DataSource = ds.Tables["wines"];
				DataGridWine.DataBind();

				ds.WriteXml(Server.MapPath("wineList.xml"));


			}

		}