Develop Reference

How to programmatically set a ASP.NET Web Forms dropdownlist selecteditem and selectedindex

I have seen multiple posts regarding this subject and the answer is pretty much the same. To set the selecteditem programmatically use the following code:
DropDownList1.DataBind(); // get the data into the list you can set it
DropDownList1.Items.FindByValue("SOMECREDITPROBLEMS").Selected = true;
My scenario is slightly different. I'm trying to set the value of a dropdownlist in a gridview.
I am able to populate the dropdownlist, but not able to set the selecteditem or selectedindex.
Gridview
<asp:GridView ID="gvSubject" runat="server"
CssClass="table table-striped clientTblEnabled"
OnRowDataBound="gvSubject_RowDataBound"
AutoGenerateColumns="false"
OnPreRender="gvSubject_PreRender"
GridLines="Both" PageSize="50">
<Columns>
<asp:TemplateField HeaderText="Subject Date">
<ItemTemplate>
<asp:Label ID="lblSubjectDate" runat="server" Text='<%# Bind("SubjectDateTime", "{0:MM/dd/yyyy}") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Subject">
<ItemTemplate>
<asp:Label ID="lblSubject" runat="server" Text='<%# Bind("SubjectDesc") %>' Visible="false"></asp:Label>
<asp:DropDownList ID="ddlSubject" runat="server" CssClass="input-xlarge controls"></asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
</Columns>
<EmptyDataTemplate>
No Results found
</EmptyDataTemplate>
</asp:GridView>
Populate dropdownlist
protected void gvSubject_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
DropDownList ddlSubject = e.Row.FindControl("ddlSubject") as DropDownList;
if (ddlSubject != null)
{
DataSet ds = GetControlData("ddlSubject");
ddlSubject.DataSource = ds.Tables[8];
ddlSubject.DataTextField = "SubjectDesc";
ddlSubject.DataValueField = "SubjectID";
ddlSubject.DataBind();
ddlSubject.Items.FindByValue((e.Row.FindControl("lblSubject") as Label).Text).Selected = true;
}
}
}
lblSubject is populated by another query in GetControlData().
When the debugger gets to the ddlSubject.Items.FindByValue code, I get a NullReferenceException even though lblSubject has a value.
I wonder if I need to change the gridview event for which I'm loading the data.

I think what you're probably after here is FindByText, not FindByValue. The value of the item will be the SubjectID column, whereas the text of the item will match the text of the label.

Adding unique row into gridview after every x rows

Intro
I'm trying to add a custom row on every 25th row. (25, 50, 75...) The custom row should be like
(start sale button)(create customer
button)(textbox)(textbox)(textbox)(textbox)(textbox)
Essentially mimicking the example gridview's format below. The reason for this is to quickly add a customer and do something with them. Moving forward once the information is inside the textboxes won't be an issue.
Using:
ASP.net
C#
The Problem
I've come across a lot of different examples for doing this, but none where I add a row that's different from the item templates that are already there. In this case having a textbox on the 25th row instead of a label. I'm not sure if this is possible or where to begin with this.
Declaration of the gridview
<asp:GridView ID="grdCustomersSearched" runat="server" AutoGenerateColumns="false" OnRowCommand="grdCustomersSearched_RowCommand" AllowPaging="True" PageSize="25" OnPageIndexChanging="grdCustomersSearched_PageIndexChanging" >
<Columns>
<asp:TemplateField HeaderText="Sale">
<ItemTemplate>
<asp:LinkButton ID="lbtnStartSale" CommandName="StartSale" CommandArgument='<%#Eval("CustomerId") %>' Text="Start Sale" runat="server">Start Sale</asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="View Profile">
<ItemTemplate>
<asp:LinkButton ID="lbtnViewCustomer" CommandName="ViewProfile" CommandArgument='<%#Eval("CustomerId") %>' Text="View Profile" runat="server">View Profile</asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Customer Number">
<ItemTemplate>
<asp:Label runat="server" Text='<%#Eval("CustomerId") %>' ID="key"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Customer Name">
<ItemTemplate>
<asp:Label runat="server" Text='<%#Eval("firstName") + " " + Eval("lastName") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Customer Address">
<ItemTemplate>
<asp:Label runat="server" Text='<%#Eval("primaryAddress") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Phone Number">
<ItemTemplate>
<asp:Label runat="server" Text='<%#Eval("primaryPhoneNumber") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="City">
<ItemTemplate>
<asp:Label runat="server" Text='<%#Eval("city") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>
<EmptyDataTemplate>
No current customer data, please search for a customer
</EmptyDataTemplate>
</asp:GridView>
Codebehind for populating gridview
The following code gathers the data that is needed and populates the gridview.
protected void btnCustomerSearch_Click(object sender, EventArgs e)
{
//Looks through database and returns a list of customers
//based on the search criteria entered
SweetShopManager ssm = new SweetShopManager();
c = ssm.GetCustomerfromSearch(txtSearch.Text);
//Binds the results to the gridview
grdCustomersSearched.Visible = true;
grdCustomersSearched.DataSource = c;
grdCustomersSearched.DataBind();
}
Example of the gridview

This can be done in the RowCreated event of a GridView. This works best with AutoGenerateColumns set to false.
int rowIndex = 0;
protected void GridView1_RowCreated(object sender, GridViewRowEventArgs e)
{
//the amount of rows in between the inserted rows
int rowsInBetween = 3;
//check if the row is a datarow
if (e.Row.RowType == DataControlRowType.DataRow && rowIndex % (rowsInBetween + 1) == 0 && rowIndex > 0)
{
//create a new row
GridViewRow extraRow = new GridViewRow(0, 0, DataControlRowType.DataRow, DataControlRowState.Insert);
extraRow.BackColor = Color.Green;
//add one cell with text
TableCell cell1 = new TableCell();
cell1.Text = "ExtraRow";
extraRow.Cells.Add(cell1);
//add another one with a textbox and column spanning
TableCell cell2 = new TableCell();
cell2.ColumnSpan = GridView1.Columns.Count - 1;
TextBox tb1 = new TextBox();
tb1.Text = "Inserted TextBox";
cell2.Controls.Add(tb1);
extraRow.Cells.Add(cell2);
//add the new row to the gridview
GridView1.Controls[0].Controls.AddAt(rowIndex, extraRow);
//extra increment the row count
rowIndex++;
}
rowIndex++;
}

Hide edit & delete button for last row in gridview

I have a gridview and few columns in gridview have amount calculations. And I have added a new datarow at the last of the gridview which sums up the column values and displays.
But the last row in gridview has edit and delete button visible and how could I possibly hide those two images from last row?
<asp:GridView ID="gvDetails" DataKeyNames="UserId,UserName" runat="server"
AutoGenerateColumns="false" CssClass="Gridview" HeaderStyle-BackColor="#61A6F8"
ShowFooter="true" HeaderStyle-Font-Bold="true" HeaderStyle-ForeColor="White"
onrowcancelingedit="gvDetails_RowCancelingEdit"
onrowdeleting="gvDetails_RowDeleting" onrowediting="gvDetails_RowEditing"
onrowupdating="gvDetails_RowUpdating">
<Columns>
<asp:TemplateField>
<EditItemTemplate>
<asp:ImageButton ID="imgbtnUpdate" CommandName="Update" runat="server" ImageUrl="~/Images/update.jpg" ToolTip="Update" Height="20px" Width="20px" />
<asp:ImageButton ID="imgbtnCancel" runat="server" CommandName="Cancel" ImageUrl="~/Images/Cancel.jpg" ToolTip="Cancel" Height="20px" Width="20px" />
</EditItemTemplate>
<ItemTemplate>
<asp:ImageButton ID="imgbtnEdit" CommandName="Edit" runat="server" ImageUrl="~/Images/Edit.jpg" ToolTip="Edit" Height="20px" Width="20px" />
<asp:ImageButton ID="imgbtnDelete" CommandName="Delete" Text="Edit" runat="server" ImageUrl="~/Images/delete.jpg" ToolTip="Delete" Height="20px" Width="20px" />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="ID">
<EditItemTemplate>
<asp:Label ID="lblID" runat="server" Text='<%#Eval("ID") %>'/>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="lblID" runat="server" Text='<%#Eval("ID") %>'/>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Profit">
<EditItemTemplate>
<asp:TextBox ID="txtProfit" runat="server" Text='<%#Eval("Profit") %>'/>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="lblProfit" runat="server" Text='<%#Eval("Profit") %>'/>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Amount">
<EditItemTemplate>
<asp:TextBox ID="txtAmount" runat="server" Text='<%#Eval("Amount") %>'/>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="lblAmount" runat="server" Text='<%#Eval("Amount") %>'/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>

You can hide them programatically:
var lastRow = gvDetails.Rows[gvDetails.Rows.Count - 1];
lastRow.FindControl("imgbtnEdit").Visible = false;
lastRow.FindControl("imgbtnDelete").Visible = false;
Ideally this should be done after grid view is data bound and has all rows (including the last one), but as a last resort you can use Page_PreRender.

The Best place for summation data is in the footer, that will take care of having the command controls as they are not added to the footer.
See: Displaying Summary Data in the Footer
Also: What is the XY Problem?
Example (should be easy to convert to C#):
'Note Global Declaration
Dim Total1 As Double = 0
Dim Total2 As Double = 0
Protected Sub GridView1_RowDataBound _
(sender As Object, e As GridViewRowEventArgs) Handles GridView1.RowDataBound
If e.Row.RowType = DataControlRowType.DataRow Then
Dim drv as DataRowView = CType(e.Row.DataItem, DataRowView)
' Perform summations on Data rows
Total1 += CDbl(drv("<column_name>").ToString())
Total2 += CDbl(drv("<other_column_name>").ToString())
ElseIf e.Row.RowType = DataControlRowType.Footer Then
' Place results in footer cells
e.Row.Cells(2).Text = "Total: " & Total1.ToString()
e.Row.Cells(3).Text = "Total: " & Total2.ToString()
Endif
End Sub

Try this
set visibility of your edit & delete button column to false. You can set the column index accordingly.
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
e.Row.Cells[0].Visible = false; //0 is autogenerate edit column index
e.Row.Cells[1].Visible = false; // 1 is autogenerate delete column index
}
}

C# getting selected value from dropdownlist in gridview asp net

How can I change the value of a textbox whenever a dropdownlist within a gridview has its value changed?
On page load, the textbox shows the selected value, but when I change the selection of the dropdownlist, the textbox value doesn't change.
The code is below.
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns = "false">
<Columns>
<asp:TemplateField HeaderText="Entry">
<ItemTemplate>
<%# Container.DataItemIndex + 1 %>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Duty">
<ItemTemplate>
<asp:DropDownList ID="duty" runat="server" OnLoad = "ddl1_load" OnSelectedIndexChanged="duty_SelectedIndexChanged" autopostback="true" EnableViewState="true"></asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
The code behind is below.
protected void ddl1_load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataTable dt = new DataTable();
Duty dy = new Duty();
dt = dy.getdutyid(Convert.ToInt32(dropcontractid.SelectedValue));
DropDownList ddl = (DropDownList)sender;
ddl.DataSource = dt;
ddl.DataTextField = "dutyid";
ddl.DataValueField = "dutyid";
ddl.DataBind();
TextBox1.Text = ddl.SelectedValue;
}
}

You need to use SelectedIndexChanged handler to show selected value:
Markup:
<asp:DropDownList ID="duty" runat="server" OnLoad="ddl1_load" OnSelectedIndexChanged="duty_SelectedIndexChanged"></asp:DropDownList>
Code-behind:
protected void duty_SelectedIndexChanged(object sender, EventArgs e)
{
GridViewRow gvr = (GridViewRow)(((Control)sender).NamingContainer);
DropDownList duty= (DropDownList) gvr.FindControl("duty");
TextBox1.Text = duty.SelectedItem.Value;
}

I had a similar problem using the DropDownLists in GridView. My solution was to adjust the onLoad for the dropdown so that it wouldn't re-write the DropDownList on every post back. This way if there's something there then it won't re-populate it.
protected void dropDownLoad(object sender, EventArgs e)
{
DropDownList dropDown = sender as DropDownList;
if (dropDown.SelectedValue == null || dropDown.SelectedValue == "")
{
// Your Code to populate table
}
}

You should look into using data binding instead. You can bind the textbox.Text to the selecteditem.value, this will ensure that proper updating takes place

this happens to me once then i code like this... but i didnt use the onLoad attribute, tell me if this works,
<asp:TemplateField HeaderText="duty" SortExpression="duty">
<EditItemTemplate>
<asp:TextBox ID="duty" runat="server" Text='<%# Bind("duty_Name") %>'></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="lblduty" runat="server" Text='<%# Eval("duty_Name") %>' />
<asp:DropDownList ID="ddlduty" runat="server" CssClass="dropdownlist"
OnLoad = "ddl1_load" OnSelectedIndexChanged="duty_SelectedIndexChanged" Visible = "false"
>
</asp:DropDownList>
</ItemTemplate>
<HeaderStyle Width="5%" />
<ItemStyle HorizontalAlign="Center" />
</asp:TemplateField>

Hidden fields in a grid won't import to a edit form

I've got a grid that only displays one piece of information such as a title. Other fields are hidden. When you click edit a modal popup displays a form and imports the information from the grid for editing. The information in hidden field are not imported though. I don't want to display all the information in the grid because I have only room for the title.
How can I make this work? Thanks. Risho
<asp:GridView ID="gvForum" runat="server" DataSourceID="odsForumApproval" DataKeyNames="id" Width="200px"
RepeatColumns="1" DataKeyField="id" CssClass="gridview"
AutoGenerateColumns="False" GridLines="None" OnSelectedIndexChanged="_OnCommand">
<AlternatingRowStyle CssClass="altbgcolor" />
<Columns>
<asp:BoundField DataField="title" />
<asp:TemplateField >
<ItemTemplate>
<asp:HiddenField runat="server" ID="hfId" Value='<%# Eval("id") %>' />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField >
<ItemTemplate>
<asp:HiddenField runat="server" ID="hfDesc" Value='<%# Eval("description") %>' />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField >
<ItemTemplate>
<asp:LinkButton ID="lnkbtn" Text="Approve" runat="server" onclick="lnkbtn_Click"/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
protected void lnkbtn_Click(object sender, EventArgs e)
{
LinkButton btndetails = sender as LinkButton;
GridViewRow gvrow = (GridViewRow)btndetails.NamingContainer;
lblID.Value = gvrow.Cells[1].Text;
txtTitle.Text = gvrow.Cells[0].Text;
lblMessage.Text = gvrow.Cells[3].Text;
this.ModalPopupExtender1.Show();
}

The Cell-Text is empty if you are using TemplateFields with nested controls . You need to get the reference to the controls and use their appropriate properties(like TextBox.Text or HiddenField.Value). Therefor you can use FindControl on the GridViewRow:
var hfId = (HiddenField)gvrow.FindControl("hfId");
var hfDesc = (HiddenField)gvrow.FindControl("hfDesc");
txtTitle.Text = gvrow.Cells[0].Text;
lblID.Value = hfId.Value;
txtTitle.Text = hfdesc.Value;