I'm using Gridview inside a repeater control to select items for billing.
but when I try to add new row in the gridview it says:
"Object reference not set to an instance of an object."
I'm using gridview to show item details and have a button to add new row to the gridview.
Below is my c# code to add new row:
private void AddNewRowToGrid()
{
foreach (RepeaterItem rptrItems in rptrTables.Items)
{
GridView gvItems = (GridView)rptrTables.FindControl("grdOrder");
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)
{
DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
DataRow drCurrentRow = dtCurrentTable.NewRow();
if (dtCurrentTable.Rows.Count > 0)
{
for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
{
DropDownList box1 = (DropDownList)gvItems.Rows[rowIndex].Cells[1].FindControl("drpItemname");
TextBox box2 = (TextBox)gvItems.Rows[rowIndex].Cells[2].FindControl("lblUnitPrice");
TextBox box3 = (TextBox)gvItems.Rows[rowIndex].Cells[3].FindControl("lblQuantity");
TextBox box4 = (TextBox)gvItems.Rows[rowIndex].Cells[4].FindControl("lblLineTotal");
drCurrentRow = dtCurrentTable.NewRow();
drCurrentRow["RowNumber"] = i + 1;
dtCurrentTable.Rows[i - 1]["ItemName"] = box1.Text;
dtCurrentTable.Rows[i - 1]["UnitPrice"] = box2.Text;
dtCurrentTable.Rows[i - 1]["Quantity"] = box3.Text;
dtCurrentTable.Rows[i - 1]["LineTotal"] = box4.Text;
rowIndex++;
}
dtCurrentTable.Rows.Add(drCurrentRow);
ViewState["CurrentTable"] = dtCurrentTable;
gvItems.DataSource = dtCurrentTable;
gvItems.DataBind();
}
}
else
{
Response.Write("ViewState is null");
}
SetPreviousData();
}
}
And here is my aspx Markup:
<div class="card-body">
<div class="row">
<div class="col-md-12">
<div class="form-group">
<asp:GridView ID="grdOrder" runat="server" AutoGenerateColumns="false" AllowPaging="true" CssClass="table table-bordered table-hover table-responsive" GridLines="None" PageSize="10" OnRowDataBound="gvRowDataBound" ShowFooter="true">
<Columns>
<asp:CommandField ShowDeleteButton="true" ControlStyle-CssClass="btn btn-danger fa fa-trash" DeleteText="" HeaderText="Remove" />
<asp:BoundField DataField="RowNumber" HeaderText="Sl. No." />
<asp:TemplateField HeaderText="Item Name">
<ItemTemplate>
<asp:DropDownList ID="drpItemname" runat="server" CssClass="form-control select2" OnSelectedIndexChanged="GetItemDetails" AutoPostBack="true"></asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Price">
<ItemTemplate>
<asp:TextBox ID="lblUnitPrice" runat="server" CssClass="form-control" Text='<%# Eval("UnitPrice")%>'></asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Qty">
<ItemTemplate>
<asp:TextBox ID="lblQuantity" runat="server" TextMode="Number" CssClass="form-control" Text='<%# Eval("Quantity")%>'></asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Line Total">
<ItemTemplate>
<asp:TextBox ID="lblLineTotal" runat="server" CssClass="form-control" Text="0"></asp:TextBox>
</ItemTemplate>
<FooterStyle HorizontalAlign="Right" />
<FooterTemplate>
<asp:Button ID="ButtonAdd" runat="server" CssClass="btn btn-primary" Text="Add" OnClick="AddItem" CausesValidation="False" />
</FooterTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</div>
</div>
</div>
</div>
<div class="card-footer">
<div class="pull-right">
<asp:Button ID="btnSubmit" runat="server" CausesValidation="false" TabIndex="2" CssClass="btn btn-primary" Text="Print KOT" />
<asp:Button ID="Button1" runat="server" CausesValidation="false" TabIndex="2" CssClass="btn btn-primary" Text="Print Final Bill" />
<asp:Button ID="Button2" runat="server" CausesValidation="false" TabIndex="2" CssClass="btn btn-primary" Text="Complete Order" />
</div>
</div>
I want to add new row to the gridview provided all the data remains intact in the previous row!
DataRow drCurrentRow = null;
at the place of this you must do
DataRow drCurrentRow= dtCurrentTable.NewRow();
because if you use NeWRow inside loop then in case your code doesn't reach inside loop your datarow object will be left with null and in that case when
dtCurrentTable.Rows.Add(drCurrentRow);
This code run it tries to add datarow instance but that is not created because that assigned to null in beginning. Or you can try
dtCurrentTable.Rows.Add(drCurrentRow);
keeping this inside loop too
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