Retain last value of add new row item

Question

User-807418713 posted

Hello

I used this in my page

https://www.c-sharpcorner.com/UploadFile/8c19e8/dynamically-adding-and-deleting-rows-in-gridview-and-saving/

For example in header3 drodpwonlist i select item1 then after i cilck add new row in new row also it will remian same value item1in header3 i want previous value to come in new added row

thanking you

Answer 1

User1535942433 posted

Hi Gopi.MCA,

Accroding to your description,I don't understand your requirment clearly.I have created a test and when I click the "add row" button,it will add a new dropdownlist with "select".Just like this:

Could you post your codes and sample to us? It will help us to solve your problems.

Best regards,

Yijing Sun

Answer 2

User-807418713 posted

Hello in hearer3 rownumber 1 you have selected item1 on add new row also I want to show item1 only not select..

Whenever add new row button click then last value to be store in header3 column drop-down

Answer 3

User-1716253493 posted

Use gridview databound event to get last value, then using findcontrol get the ddl from the headerrow. Select the item you want

Or use session variabel or viewstate variable, set the value while inserting data. Then like above way set selected ddl from the variable in databound event

Answer 4

User1535942433 posted

Hi Gopi.MCA,

Accroding to your description,as far as I think,you could viewstate datatable value in rowdatabound event.

Just like this:

 <asp:GridView ID="Gridview1" runat="server" ShowFooter="true"
                AutoGenerateColumns="false"
                OnRowCreated="Gridview1_RowCreated" OnRowDataBound="Gridview1_RowDataBound">
                <Columns>
                    <asp:BoundField DataField="RowNumber" HeaderText="Row Number" />
                    <asp:TemplateField HeaderText="Header 1">
                        <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="Header 3">
                        <ItemTemplate>
                            <asp:DropDownList ID="DropDownList1" runat="server"
                                AppendDataBoundItems="true">
                                <asp:ListItem Value="-1">Select</asp:ListItem>
                            </asp:DropDownList>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Header 4">
                        <ItemTemplate>
                            <asp:DropDownList ID="DropDownList2" runat="server"
                                AppendDataBoundItems="true">
                                <asp:ListItem Value="-1">Select</asp:ListItem>
                            </asp:DropDownList>
                        </ItemTemplate>
                        <FooterStyle HorizontalAlign="Right" />
                        <FooterTemplate>
                            <asp:Button ID="ButtonAdd" runat="server"
                                Text="Add New Row" 
                                OnClick="ButtonAdd_Click" />
                        </FooterTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField>
                        <ItemTemplate>
                            <asp:LinkButton ID="LinkButton1" runat="server"
                                OnClick="LinkButton1_Click">Remove</asp:LinkButton>
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
            </asp:GridView>

Code-behind:

 private ArrayList GetDummyData()
        {

            ArrayList arr = new ArrayList();

            arr.Add(new ListItem("Item1", "1"));
            arr.Add(new ListItem("Item2", "2"));
            arr.Add(new ListItem("Item3", "3"));
            arr.Add(new ListItem("Item4", "4"));
            arr.Add(new ListItem("Item5", "5"));

            return arr;
        }

        private void FillDropDownList(DropDownList ddl)
        {
            ArrayList arr = GetDummyData();

            foreach (ListItem item in arr)
            {
                ddl.Items.Add(item);
            }
        }

        private void SetInitialRow()
        {

            DataTable dt = new DataTable();
            DataRow dr = null;

            dt.Columns.Add(new DataColumn("RowNumber", typeof(string)));
            dt.Columns.Add(new DataColumn("Column1", typeof(string)));//for TextBox value   
            dt.Columns.Add(new DataColumn("Column2", typeof(string)));//for TextBox value   
            dt.Columns.Add(new DataColumn("Column3", typeof(string)));//for DropDownList selected item   
            dt.Columns.Add(new DataColumn("Column4", typeof(string)));//for DropDownList selected item   

            dr = dt.NewRow();
            dr["RowNumber"] = 1;
            dr["Column1"] = string.Empty;
            dr["Column2"] = string.Empty;
            dt.Rows.Add(dr);

            //Store the DataTable in ViewState for future reference   
            ViewState["CurrentTable"] = dt;

            //Bind the Gridview   
            Gridview1.DataSource = dt;
            Gridview1.DataBind();

            //After binding the gridview, we can then extract and fill the DropDownList with Data   
            DropDownList ddl1 = (DropDownList)Gridview1.Rows[0].Cells[3].FindControl("DropDownList1");
            DropDownList ddl2 = (DropDownList)Gridview1.Rows[0].Cells[4].FindControl("DropDownList2");
            FillDropDownList(ddl1);
            FillDropDownList(ddl2);
        }

        private void AddNewRowToGrid()
        {

            if (ViewState["CurrentTable"] != null)
            {

                DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
                DataRow drCurrentRow = null;

                if (dtCurrentTable.Rows.Count > 0)
                {
                    drCurrentRow = dtCurrentTable.NewRow();
                    drCurrentRow["RowNumber"] = dtCurrentTable.Rows.Count + 1;

                    //add new row to DataTable   
                    dtCurrentTable.Rows.Add(drCurrentRow);
                    //Store the current data to ViewState for future reference   

                    ViewState["CurrentTable"] = dtCurrentTable;


                    for (int i = 0; i < dtCurrentTable.Rows.Count - 1; i++)
                    {

                        //extract the TextBox values   

                        TextBox box1 = (TextBox)Gridview1.Rows[i].Cells[1].FindControl("TextBox1");
                        TextBox box2 = (TextBox)Gridview1.Rows[i].Cells[2].FindControl("TextBox2");

                        dtCurrentTable.Rows[i]["Column1"] = box1.Text;
                        dtCurrentTable.Rows[i]["Column2"] = box2.Text;

                        //extract the DropDownList Selected Items   

                        DropDownList ddl1 = (DropDownList)Gridview1.Rows[i].Cells[3].FindControl("DropDownList1");
                        DropDownList ddl2 = (DropDownList)Gridview1.Rows[i].Cells[4].FindControl("DropDownList2");

                        dtCurrentTable.Rows[i]["Column3"] = ddl1.SelectedItem.Text;
                        dtCurrentTable.Rows[i]["Column4"] = ddl2.SelectedItem.Text;

                        // Update the DataRow with the DDL Selected Items   
                    }
                    //Rebind the Grid with the current data to reflect changes   
                    Gridview1.DataSource = dtCurrentTable;
                    Gridview1.DataBind();
                }
            }
            else
            {
                Response.Write("ViewState is null");

            }
            //Set Previous Data on Postbacks   
            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++)
                    {

                        TextBox box1 = (TextBox)Gridview1.Rows[i].Cells[1].FindControl("TextBox1");
                        TextBox box2 = (TextBox)Gridview1.Rows[i].Cells[2].FindControl("TextBox2");

                        DropDownList ddl1 = (DropDownList)Gridview1.Rows[rowIndex].Cells[3].FindControl("DropDownList1");
                        DropDownList ddl2 = (DropDownList)Gridview1.Rows[rowIndex].Cells[4].FindControl("DropDownList2");

                        //Fill the DropDownList with Data   
                        FillDropDownList(ddl1);
                        FillDropDownList(ddl2);


                        if (i < dt.Rows.Count - 1)
                        {

                            //Assign the value from DataTable to the TextBox   
                            box1.Text = dt.Rows[i]["Column1"].ToString();
                            box2.Text = dt.Rows[i]["Column2"].ToString();

                            //Set the Previous Selected Items on Each DropDownList  on Postbacks   
                            ddl1.ClearSelection();
                            ddl1.Items.FindByText(dt.Rows[i]["Column3"].ToString()).Selected = true;

                            ddl2.ClearSelection();
                            ddl2.Items.FindByText(dt.Rows[i]["Column4"].ToString()).Selected = true;

                        }

                        rowIndex++;
                    }
                }
            }
        }

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

        protected void ButtonAdd_Click(object sender, EventArgs e)
        {
            AddNewRowToGrid();
        }

        protected void Gridview1_RowCreated(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                DataTable dt = (DataTable)ViewState["CurrentTable"];
                LinkButton lb = (LinkButton)e.Row.FindControl("LinkButton1");
                if (lb != null)
                {
                    if (dt.Rows.Count > 1)
                    {
                        if (e.Row.RowIndex == dt.Rows.Count - 1)
                        {
                            lb.Visible = false;
                        }
                    }
                    else
                    {
                        lb.Visible = false;
                    }
                }
            }
        }

        protected void LinkButton1_Click(object sender, EventArgs e)
        {
            LinkButton lb = (LinkButton)sender;
            GridViewRow gvRow = (GridViewRow)lb.NamingContainer;
            int rowID = gvRow.RowIndex;
            if (ViewState["CurrentTable"] != null)
            {

                DataTable dt = (DataTable)ViewState["CurrentTable"];
                if (dt.Rows.Count > 1)
                {
                    if (gvRow.RowIndex < dt.Rows.Count - 1)
                    {
                        //Remove the Selected Row data and reset row number  
                        dt.Rows.Remove(dt.Rows[rowID]);
                        ResetRowID(dt);
                    }
                }

                //Store the current data in ViewState for future reference  
                ViewState["CurrentTable"] = dt;
                //Re bind the GridView for the updated data  
                Gridview1.DataSource = dt;
                Gridview1.DataBind();
            }

            //Set Previous Data on Postbacks  
            SetPreviousData();
        }

        private void ResetRowID(DataTable dt)
        {
            int rowNumber = 1;
            if (dt.Rows.Count > 0)
            {
                foreach (DataRow row in dt.Rows)
                {
                    row[0] = rowNumber;
                    rowNumber++;
                }
            }
        }

        protected void Gridview1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                var dropdownList = e.Row.FindControl("DropDownList1") as DropDownList;
                if (e.Row.RowIndex != 0)
                {
                    DataTable dtAgents = (DataTable)ViewState["CurrentTable"];
                    for (int i = 0; i < dtAgents.Rows.Count; i++)
                    {
                        if (i == 0)
                        {
                            var predropdownList = dtAgents.Rows[i]["Column3"].ToString();
                            dropdownList.SelectedItem.Text = predropdownList;
                        }
                        else
                        {
                            var predropdownList = dtAgents.Rows[i - 1]["Column3"].ToString();
                            dropdownList.SelectedItem.Text = predropdownList;
                        }
                    }
                }
                
                
            }
        }

Result:

Best regards,

Yijing Sun