Here is the source:

JAVASCRIPT:

function Button2_onclick() 

{

    var grid = ISGetObject("WebGrid1");

    var table = grid.RootTable;

    alert(grid.TotalRows);

   var row4 = grid.RootTable.GetRow(0);

   var row5 = grid.RootTable.GetRow(1);

   var row6 = grid.RootTable.GetRow(2);

}

SERVER SIDE:

   using System;

using System.Data;

using ISNet.WebUI.WebGrid;

using System.Web.UI.WebControls;

using System.Drawing;

using ISNet.WebUI;

using System.Collections.Generic;

public partial class _Default : System.Web.UI.Page

{

    protected void Page_Load(object sender, EventArgs e)

    {

        WebGrid1.InitializeLayout += new LayoutEventHandler(ctlUltraGrid_InitializeLayout);

        WebGrid1.InitializeDataSource += new DataSourceEventHandler(WebGrid1_InitializeDataSource);

        WebGrid1.PrepareDataBinding += new DataSourceEventHandler(WebGrid1_PrepareDataBinding);

    }

    protected override void OnPreRender(EventArgs e)

    {

        WebGrid1.RootTable.Rows[3].Visible = false;

        WebGrid1.RootTable.Rows[2].Visible = false;

       // WebGrid1.RootTable.Rows.RemoveAt(2);

    }

    protected void ctlUltraGrid_InitializeLayout(object sender, ISNet.WebUI.WebGrid.LayoutEventArgs e)

    {

        if (!IsPostBack)

        {

            //Create the column

            WebGridColumn wcol = new WebGridColumn("ItemName", "ItemName");

            WebGrid1.RootTable.Columns.Add(wcol);

            WebGridColumn wcol1 = new WebGridColumn("Discount", "Discount");

            WebGrid1.RootTable.Columns.Add(wcol1);

            WebGridColumn wcol2 = new WebGridColumn("Price", "Price");

            WebGrid1.RootTable.Columns.Add(wcol2);

            WebGrid1.RootTable.Layout.ColumnHeaders = ColumnVisibility.No;

        }

        e.Layout.ClientSideEvents.OnRowSelect = "DoRowSelect";

    }

    protected void WebGrid1_InitializeDataSource(object sender, DataSourceEventArgs e)

    {

        if (!IsPostBack)

            e.DataSource = GetTable();

        else

            e.DataSource = ViewState["oo"]; 

    }

    DataTable GetTable()

    {

        //

        // Here we create a DataTable with four columns.

        //

        DataTable table = new DataTable();

        table.Columns.Add("Dosage", typeof(int));

        table.Columns.Add("Drug", typeof(string));

        table.Columns.Add("Patient", typeof(string));

        //

        // Here we add five DataRows.

        //

        table.Rows.Add(25, "Indocin", "David");

        table.Rows.Add(50, "Enebrel", "Sam");

        table.Rows.Add(10, "Hydralazine", "Christoff");

        table.Rows.Add(13, "Hydralazine1", "Christof1f");

        table.Rows.Add(15, "Hydralazine2", "Christof2f");

        table.Rows.Add(16, "Hydralazin3e", "Christof3f");

        return table;

    }

    protected void WebGrid1_PrepareDataBinding(object sender, DataSourceEventArgs e)

    {

        WebGrid1.RetrieveStructure();

        foreach (WebGridColumn item in WebGrid1.RootTable.Columns)

        {

            item.CellStyle.BackColor = System.Drawing.Color.Pink;

            if (item.Position == WebGrid1.RootTable.Columns.Count - 1)

                item.EditType = EditType.NoEdit;

            else

                item.EditType = EditType.NoEdit;

        }

        var dt = WebGrid1.GetCachedDataSource();

        ViewState["oo"] = dt;

    }

}

Hello,

Thank you for the question regarding WebGrid.

Here’s the example snippet code how to hide a row in WebGrid from server side:

protected void Button1_Click(object sender, EventArgs e){
    //Hide the 2nd row
    WebGrid1.RootTable.Rows[1].Visible = false;
}

If you want to hide a row when WebGrid being loaded, you can use InitializeRow server side event.
Here the example snippet code:

protected void WebGrid1_InitializeRow(object sender, ISNet.WebUI.WebGrid.RowEventArgs e)
{
    // Hide the 3rd row
    if (e.Row.KeyValue.ToString() == "3")
        e.Row.Visible = false;
}

I attached the sample the use those code above. You could have review on the sample to see the result.
I bind the WebGrid to access data source (Northwind.mdb database & Shippers table).

You could download the sample from this link as well: http://1drv.ms/1kaksJq

Regards,
Hans K.