how to delete textboxes dynamically

cs code

 protected void DeleteNewRowToGrid()
    {
        int rowIndex = 0; 
        if (ViewState["dtCurrentTable"] != null)
        {
            DataTable DeldtCurrentTable = (DataTable)ViewState["dtCurrentTable"];
            DataRow drCurrentRow = null;
            if (DeldtCurrentTable.Rows.Count > 0)
            {
                for (int i = 1; i > DeldtCurrentTable.Rows.Count; i--)
                {
                    //extract the TextBox values
                    TextBox box1 = (TextBox)Gridview1.Rows[rowIndex].Cells[1].FindControl("TextBox1");
                    //TextBox box2 = (TextBox)Gridview1.Rows[rowIndex].Cells[2].FindControl("TextBox2");
                    DropDownList box2 = (DropDownList)Gridview1.Rows[rowIndex].Cells[2].FindControl("ddldatatype");

                    drCurrentRow = DeldtCurrentTable.NewRow();
                    drCurrentRow["RowNumber"] = i - 1;
                    drCurrentRow["Column1"] = box1.Text;
                    drCurrentRow["Column2"] = box2.Text;
                    //drCurrentRow["Column3"] = box3.Text;

                    rowIndex--;
                }
                //add new row to DataTable
                DeldtCurrentTable.Rows.Remove(drCurrentRow);
                //Store the current data to ViewState
                ViewState["dtCurrentTable"] = DeldtCurrentTable;

                //Rebind the Grid with the current开发者_开发技巧 data
                Gridview1.DataSource = DeldtCurrentTable;
                Gridview1.DataBind();
            }
        }
    }

    protected void ButtonDel_Click(object sender, EventArgs e)
    {
        DeleteNewRowToGrid();
    }
aspx code

 <asp:gridview ID="Gridview1" runat="server" ShowFooter="true" AutoGenerateColumns="false">
        <Columns>
        <asp:BoundField DataField="RowNumber" HeaderText="Row Number" />
        <asp:TemplateField HeaderText="Column Name">
            <ItemTemplate>
                <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
            </ItemTemplate>
        </asp:TemplateField>
     <%-- <asp:TemplateField HeaderText="Header 2">
            <ItemTemplate>
                <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
            </ItemTemplate>
        </asp:TemplateField>--%>
        <asp:TemplateField HeaderText="Data Type">
            <ItemTemplate>
                  <asp:DropDownList ID="ddldatatype" runat="server">
                  <asp:ListItem>varchar</asp:ListItem>
                  <asp:ListItem>int</asp:ListItem>
                  <asp:ListItem>numeric</asp:ListItem>
                  <asp:ListItem>uniqueidentifier</asp:ListItem>
                  <asp:ListItem>char</asp:ListItem>
                  </asp:DropDownList>
            </ItemTemplate>
            <FooterStyle HorizontalAlign="Right" />
            <FooterTemplate>
            <asp:Button ID="ButtonAdd" runat="server" Text="Add New Row" OnClick="ButtonAdd_Click"/>
             <asp:Button ID="ButtonDel" runat="server" Text="Delete Row" OnClick="ButtonDel_Click"/>
             <input type="hidden" runat="server" value="0" id="hiddencount" />
            </FooterTemplate>
        </asp:TemplateField>
        </Columns>
</asp:gridview>

I have done with add rwo, now I want to delete

you are trying to deleta a row "drCurrentRow" that's not even in your DataTable, because you created this drCurrentRow = DeldtCurrentTable.NewRow(); yourself and didn't even insert it (no use anyway).

You have to search the rows to delete from your source like this:

var toDel = DeldtCurrentTable.Where(row => /* true if found */).ToArray();
foreach(var t in toDel) DeldtCurrentTable.Rows.Remove(t);

and then you can reiterate and set your rownumbers again.

Finaly set the the ViewState and the DataSource + DataBind it

BTW: your naming is really frustrating - what the heck does "DeleteNewRowToGrid" mean? Do you want to delete some new row? What is the a new row in this case? So: Which row should be deleted here?