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New Blank Gridview Row

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User-705944790 posted

I've written some code so that when a button is clicked in the grid it adds a new row, it all works perfectly until I add a checkbox, getting a cast error when the gridview databinds any help is appreciated.

private void AddNewRowToGrid()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)
{
DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];

DataRow drCurrentRow = null;

if (dtCurrentTable.Rows.Count > 0)
{
for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
{
Label box2 = (Label)gvBookItems.Rows[rowIndex].Cells[2].FindControl("lblEBookOutID");
Label box3 = (Label)gvBookItems.Rows[rowIndex].Cells[3].FindControl("lblECopyNumber");
Label box4 = (Label)gvBookItems.Rows[rowIndex].Cells[4].FindControl("lblEBookedOutDate");
CheckBox box5 = (CheckBox)gvBookItems.Rows[rowIndex].Cells[5].FindControl("chkELTL");
Label box6 = (Label)gvBookItems.Rows[rowIndex].Cells[6].FindControl("lblEBookedOutBy");
drCurrentRow = dtCurrentTable.NewRow();
rowIndex++;
}
dtCurrentTable.Rows.Add(drCurrentRow);
ViewState["CurrentTable"] = dtCurrentTable;
gvBookItems.DataSource = dtCurrentTable;

//Code is failing here........receiving cast error once it's created the new row...........
gvBookItems.DataBind();

            }

        }
else
{

Response.Write("ViewState is null");

        }

        SetPreviousData();

    }

private void SetPreviousData()
    {
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)

        {

DataTable dt = (DataTable)ViewState["CurrentTable"];

if (dt.Rows.Count > 0)
{

for (int i = 0; i < dt.Rows.Count; i++)
{

if (i != dt.Rows.Count-1)
{

Label box2 = (Label)gvBookItems.Rows[rowIndex].Cells[2].FindControl("lblEBookOutID");
Label box3 = (Label)gvBookItems.Rows[rowIndex].Cells[3].FindControl("lblECopyNumber");
Label box4 = (Label)gvBookItems.Rows[rowIndex].Cells[4].FindControl("lblEBookedOutDate");
CheckBox box5 = (CheckBox)gvBookItems.Rows[rowIndex].Cells[5].FindControl("chkELTL");
Label box6 = (Label)gvBookItems.Rows[rowIndex].Cells[6].FindControl("lblEBookedOutBy");
rowIndex++;
}

else
    {
Label box2 = (Label)gvBookItems.Rows[rowIndex].Cells[2].FindControl("lblEEBookOutID");
TextBox box3 = (TextBox)gvBookItems.Rows[rowIndex].Cells[3].FindControl("txtEECopyNumber");
TextBox box4 = (TextBox)gvBookItems.Rows[rowIndex].Cells[4].FindControl("txtEEBookedOutDate");
CheckBox box5 = (CheckBox)gvBookItems.Rows[rowIndex].Cells[5].FindControl("chkEELTL");
TextBox box6 = (TextBox)gvBookItems.Rows[rowIndex].Cells[6].FindControl("txtEEBookedOutBy");

rowIndex++;

                    }

                }

            }

        }

Friday, September 30, 2016 2:03 PM

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User36583972 posted

Hi RobM47,

From your description, I have made a sample on my side. It is working.

You can refer the following code.

ASPX:

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
                <Columns>
                    <asp:TemplateField>
                        <ItemTemplate>
                            <%--<asp:CheckBox ID="CheckBox1" runat="server"
                                AutoPostBack="true" 
                                Text='<%# Eval("Checked").ToString() %>' />--%>
                            <asp:CheckBox ID="chkStatus" runat="server"
                                AutoPostBack="true" 
                                Checked='<%# Convert.ToBoolean(Eval("Checked").ToString().Equals("1") ? " True " : "False") %>'
                                Text='<%# Eval("Checked").ToString().Equals("1") ? " Checked " : " Not Checked " %>' />
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:BoundField DataField="CustomerId" HeaderText="CustomerId" ItemStyle-Width="30" />
                    <asp:BoundField DataField="Name" HeaderText="Name" ItemStyle-Width="150" />
                    <asp:BoundField DataField="Count" HeaderText="Count" ItemStyle-Width="150" />
                </Columns>
            </asp:GridView>

ASPX.CS:

     protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                bind();
            }
        }

        private void bind()
        {
            DataTable tblDatas = new DataTable("Datas");
            DataColumn dc = null;
            dc = tblDatas.Columns.Add("CustomerId", Type.GetType("System.Int32"));
            dc = tblDatas.Columns.Add("Name", Type.GetType("System.String"));
            dc = tblDatas.Columns.Add("Count", Type.GetType("System.Int32"));
            dc = tblDatas.Columns.Add("Checked", Type.GetType("System.String"));
            DataRow newRow;
            for (int i = 0; i < 6; i++)
            {
                newRow = tblDatas.NewRow();
                newRow["CustomerId"] = i + 1;
                newRow["Name"] = "Count" + i.ToString();
                newRow["Count"] = 20 + (i * 2);
                newRow["Checked"] = "1";
                tblDatas.Rows.Add(newRow);
            }
            ViewState["dt"] = tblDatas;
            GridView1.DataSource = tblDatas;
            GridView1.DataBind();
        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            int rowIndex = 0;

            DataTable dtCurrentTable = (DataTable)ViewState["dt"];
            if (dtCurrentTable.Rows.Count > 0)
            {
                DataRow drCurrentRow = null;
                for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
                {       
                    drCurrentRow = dtCurrentTable.NewRow();
                    rowIndex++;
                }
                dtCurrentTable.Rows.Add(drCurrentRow);
                ViewState["dt"] = dtCurrentTable;
                GridView1.DataSource = dtCurrentTable;
                GridView1.DataBind();

            }

        }

Best Regards,

Yohann Lu

Sunday, October 2, 2016 6:37 AM

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User-705944790 posted

Hi.
Many thanks for your reply, this works great if you are not binding to a database, my version works if you don't connect to a database. The Checkboxes don't populate correctly as per the data. Having issues when pressing the Create button in the grid to add a new blank row for EditItemTemplate.

My HTML is

<asp:GridView ID="gvBookItems" runat="server" CssClass="ItemGridFormatting" AutoGenerateColumns="False" CellPadding="3" CellSpacing="3" Width="1200px" Height="60px" OnRowEditing="gvBookItems_RowEditing" OnRowCommand="gvBookItems_RowCommand">
<Columns>
<asp:TemplateField HeaderText="Edit Item">
<ItemTemplate>
<asp:ImageButton ID="imgbtnEditBI" runat="server" ImageUrl="~/Graphics/EditIcon.png" CommandName="Edit" ToolTip="Select record" />
</ItemTemplate>
<EditItemTemplate>
<asp:ImageButton ID="imgbtnUpdateBI" runat="server" ImageUrl="~/Graphics/UpdateIcon.png" CommandName="UpdateBI" ToolTip="Update Booking Item"/>
</EditItemTemplate>
<ItemStyle HorizontalAlign="Center" Width="50px" />
</asp:TemplateField>

<asp:TemplateField HeaderText="Create">
<ItemTemplate>
<asp:ImageButton ID="imgbtnAddBI" runat="server" ImageUrl="~/Graphics/AddIcon.png" CommandName="CreateBI" ToolTip="Create Booking Item" />
</ItemTemplate>
<EditItemTemplate>
<asp:ImageButton ID="imgbtnCanEdit" runat="server" CommandName="CancelEdit" ImageUrl="~/graphics/CancelIcon.png" ToolTip="Cancel Amendment" />
</EditItemTemplate>
<ItemStyle HorizontalAlign="Center" Width="40px" />                    </asp:TemplateField>

<asp:TemplateField HeaderText="Book Out ID">
<ItemTemplate>
<asp:Label ID="lblEBookOutID" runat="server" Text='<%# Bind("BookOutID") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:Label ID="lblEEBookOutID" runat="server" Text='<%# Bind("BookOutID") %>'></asp:Label>
</EditItemTemplate>
<ItemStyle Width="40px" HorizontalAlign="Center" />                     </asp:TemplateField>
<asp:TemplateField HeaderText="Booked Out To">                     <ItemTemplate>
<asp:Label ID="lblECustomerID" runat="server" Text='<%# Bind("CustomerID") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txtEECustomerID" runat="server" Width="40px" CssClass="stdtextboxeshorizAlt" Text='<%# Bind("CustomerID") %>'></asp:TextBox>                      </EditItemTemplate>
<ItemStyle Width="40px" HorizontalAlign="Center" />                      </asp:TemplateField>
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:Label ID="lblEName" runat="server" Text='<%# Bind("BookedName") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txtEEName" runat="server" Width="200px" CssClass="stdtextboxeshorizAlt" Text='<%# Bind("BookedName") %>'></asp:TextBox>                      </EditItemTemplate>
<ItemStyle Width="200px" HorizontalAlign="Center" />                     </asp:TemplateField>
<asp:TemplateField HeaderText="LT Loan">
<ItemTemplate>
<asp:CheckBox ID="chkELTL" runat="server" Checked='<%# Convert.ToBoolean(Eval("LongTermLoan")) %>' />
</ItemTemplate>
<EditItemTemplate>
<asp:CheckBox ID="chkEELTL" runat="server" Checked='<%# Convert.ToBoolean(Eval("LongTermLoan")) %>'/>                      </EditItemTemplate>
<ItemStyle Width="40px" HorizontalAlign="Center" />                     </asp:TemplateField>
<asp:TemplateField HeaderText="Return Due">
<ItemTemplate>
<asp:Label ID="lblELoanRetDate" runat="server" Text='<%# Bind("LoanReturnDate","{0:dd/MM/yyyy}") %>'></asp:Label>                         </ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txtEELoanRetDate" runat="server" Width="90px" CssClass="stdtextboxeshorizAlt" Text='<%# Bind("LoanReturnDate","{0:dd/MM/yyyy}") %>'></asp:TextBox>                     </EditItemTemplate>
<ItemStyle Width="90px" HorizontalAlign="Center" />                     </asp:TemplateField>
<asp:TemplateField HeaderText="Returned Date">                      <ItemTemplate>
<asp:Label ID="lblEReturnedDate" runat="server" Text='<%# Bind("ReturnedDate","{0:dd/MM/yyyy}") %>'></asp:Label>                        </ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txtEEReturnedDate" runat="server" Width="90px" CssClass="stdtextboxeshorizAlt" Text='<%# Bind("ReturnedDate","{0:dd/MM/yyyy}") %>'></asp:TextBox>
</EditItemTemplate>
<ItemStyle Width="90px" HorizontalAlign="Center" />                     </asp:TemplateField>
</asp:GridView>

C# Code is

I do have try and catch etc, have also cut some of the names out to cut down the code

A search button executes the following code which retrieves the main record, the following below retrieves the sub items

protected bool RetrievePt2BookItems()
{
cmd = new SqlCommand("spBookItemsRetrieve", connASP);
cmd.CommandType = CommandType.StoredProcedure;
param = cmd.Parameters.Add("@ASPCI", SqlDbType.Int);
param.Value = txtConfigNumber.Text;
connASP.Open();

//I added the following code and receive a different error            //SqlDataAdapter sda1 = new SqlDataAdapter(cmd);
//DataTable tblBook = new DataTable();
//DataColumn dc = null;
//dc = tblBook.Columns.Add("@BookOutID", Type.GetType("System.Int32"));            //dc = tblBook.Columns.Add("@CustomerID", Type.GetType("System.Int32"));            //dc = tblBook.Columns.Add("@BookedName", Type.GetType("System.String"));            //dc = tblBook.Columns.Add("@LongTermLoan", Type.GetType("System.Boolean"));            //dc = tblBook.Columns.Add("@LoanReturnDate", Type.GetType("System.DateTime"));            //sda1.Fill(tblBook);
//ViewState["dt"] = tblBook;
//gvBookItems.DataSource = tblBook;
//gvBookItems.DataBind();

//I went back to this code

SqlDataAdapter sda1 = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
sda1.Fill(dt);
ViewState["CurrentTable"] = dt;
gvBookItems.DataSource = dt;
gvBookItems.DataBind();
}

private void AddNewRowToGrid()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null) { DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];

DataRow drCurrentRow = null;

if (dtCurrentTable.Rows.Count > 0) { for (int i = 1; i <= dtCurrentTable.Rows.Count; i++) { Label box2 = (Label)gvBookItems.Rows[rowIndex].Cells[2].FindControl("lblEBookOutID"); Label box3 = (Label)gvBookItems.Rows[rowIndex].Cells[3].FindControl("lblECopyNumber"); Label box4 = (Label)gvBookItems.Rows[rowIndex].Cells[4].FindControl("lblEBookedOutDate"); CheckBox box5 = (CheckBox)gvBookItems.Rows[rowIndex].Cells[5].FindControl("chkELTL"); Label box6 = (Label)gvBookItems.Rows[rowIndex].Cells[6].FindControl("lblEBookedOutBy"); drCurrentRow = dtCurrentTable.NewRow(); rowIndex++; } dtCurrentTable.Rows.Add(drCurrentRow); ViewState["CurrentTable"] = dtCurrentTable;                gvBookItems.DataSource = dtCurrentTable;
//Code is failing here........receiving cast error once it's created the new row........... gvBookItems.DataBind();

            }

        } else {

Response.Write("ViewState is null");

        }

        SetPreviousData();

    }

private void SetPreviousData()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)

        {

DataTable dt = (DataTable)ViewState["CurrentTable"];

if (dt.Rows.Count > 0) {

for (int i = 0; i < dt.Rows.Count; i++) {

if (i != dt.Rows.Count-1) {

Label box2 = (Label)gvBookItems.Rows[rowIndex].Cells[2].FindControl("lblEBookOutID"); Label box3 = (Label)gvBookItems.Rows[rowIndex].Cells[3].FindControl("lblECopyNumber"); Label box4 = (Label)gvBookItems.Rows[rowIndex].Cells[4].FindControl("lblEBookedOutDate"); CheckBox box5 = (CheckBox)gvBookItems.Rows[rowIndex].Cells[5].FindControl("chkELTL"); Label box6 = (Label)gvBookItems.Rows[rowIndex].Cells[6].FindControl("lblEBookedOutBy"); rowIndex++; }

else     { Label box2 = (Label)gvBookItems.Rows[rowIndex].Cells[2].FindControl("lblEEBookOutID"); TextBox box3 = (TextBox)gvBookItems.Rows[rowIndex].Cells[3].FindControl("txtEECopyNumber"); TextBox box4 = (TextBox)gvBookItems.Rows[rowIndex].Cells[4].FindControl("txtEEBookedOutDate"); CheckBox box5 = (CheckBox)gvBookItems.Rows[rowIndex].Cells[5].FindControl("chkEELTL"); TextBox box6 = (TextBox)gvBookItems.Rows[rowIndex].Cells[6].FindControl("txtEEBookedOutBy");

rowIndex++;

                    }

                }

            }

        }



protected void gvBookItems_RowCommand(object sender, GridViewCommandEventArgs e)
    {
if (e.CommandName == "CreateBI")
{
GridViewRow row = (GridViewRow)(((ImageButton)e.CommandSource).NamingContainer);
index = gvBookItems.Rows.Count;
ASPNo = txtConfigNumber.Text;
gvBookItems.EditIndex = index;
AddNewRowToGrid();
}

}

The ERROR Message is Object cannot be cast from DBNull, this is when I click the CreateBI button in the grid to add a new row

Monday, October 3, 2016 10:57 AM
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User36583972 posted

Hi RobM47,

The ERROR Message is Object cannot be cast from DBNull, this is when I click the CreateBI button in the grid to add a new row

I suggest you can add a check for the Object that like the below.

if(Object == DBNull.Value)

You can add RowDataBound event for your GridView and check which rows cause the cast error.

RowDataBound Event in GridView in ASP.Net:

http://www.c-sharpcorner.com/UploadFile/1e050f/rowdatabound-event-in-gridview-in-Asp-Net/

Best Regards,

Yohann Lu
Wednesday, October 12, 2016 9:47 AM

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New Blank Gridview Row

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