I have been trying to understand the ListView object in ASP but I'm unable to programmatically get the selected checkboxes or iterate through them. Below are the two methods I'm seeing posted the most here on SO, but so far everything I've tried hasn't seemed to work for me.
Any help would greatly be appreciated.
.ASPX Page
<asp:ListView ID="courseListView" runat="server">
<LayoutTemplate>
<table><asp:PlaceHolder runat="server" ID="itemPlaceholder">
</asp:PlaceHolder></table>
</LayoutTemplate>
<ItemTemplate>
<tr>
<td><asp:CheckBox ID="courseIdchk" Text='<%# Eval("CourseId") %>' runat="server" /></td>
<td><asp:Label ID="courseTitleLbl" Text='<%# Eval("title") %>' runat="server" /></td>
</tr>
</ItemTemplate>
</asp:ListView>
.CS Code Behind
//Method #1
string result = string.Join(", ", courseListView.Controls.OfType<CheckBox>()
.Select(chk => chk.Text));
string result = "";
//Method #2
foreach (CheckBox ctrl in courseListView.Controls.OfType<CheckBox>())
{
result2 += ctrl.Text;
}
Response.Write("<p>The result is " + result);
Response.Write("<p>The result is " + result2);
Response.End();
I'm not near the Visual Studio but off the top of my head I see 2 reasons why it does not iterate.
1. You should bind this ListView to a source in OnLoad method:
if (!IsPostback) {
courseListView.DataSource = GetCourses();
courseListView.DataBind();
}
2. courseListView.Controls does not contain items of type CheckBox, so OfType<CheckBox>() filters out all elements. If you debug and put a breakpoint over foreach (CheckBox ctrl in courseListView.Controls.OfType<CheckBox>()), you will see that CheckBox is one of the subchildren of courseListView., so build your logic depending on which control contain CheckBoxes write the appropriate logic to get it like:
var checkBox = courseListView.Controls.Cast<Control>().First().FindControl("courseIdchk");
Again, the code above assumes that checkbox is a child of a control, which is an only child of your courseListView.
UPDATE
var findCheckedQuery = courseListView.Controls[0]
.Controls
.Cast<Control>()
.Select(ctrl => ctrl.FindControl("chkBox") as CheckBox)
.Where(chk => chk != null && chk.Checked);
result = string.Join(":", findCheckedQuery.Select(x => x.Text).ToArray());
UPDATE2
ASPX:
<asp:Repeater ID="courseListView" runat="server">
<ItemTemplate>
<asp:CheckBox ID="chkBox" data-id="<%#((Course)Container.DataItem).CourseId %>" Text="<%#((Course)Container.DataItem).Title %>" runat="server" />
<br/>
</ItemTemplate>
</asp:Repeater>
<asp:Button runat="server" UseSubmitBehavior="True" Text="Submit"/>
Code-behind:
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
if (!IsPostBack)
{
courseListView.DataSource = GetCourses();
courseListView.DataBind();
}
else
{
var result = string.Empty;
var findCheckedQuery = courseListView
.Controls
.Cast<Control>()
.Select(x => (CheckBox)x.FindControl("chkBox"))
.Where(x => x.Checked)
.Select(x => x.Text);
result = string.Join(", ", findCheckedQuery.ToArray());
}
}
Related
I am trying to find the formview inside my listview on the page load. However, my result is always null. I called the DataBind method first but still nothing.
Code Behind
protected void Page_Load(object sender, EventArgs e)
{
String list = itemdropdownlist.SelectedValue;
switch (list)
{
case "Section Item":
SectionListView.DataBind();
//SectionListView.Enabled = false;
var temp = (FormView)SectionListView.FindControl("SectionFormView");
temp.Enabled = true;
renderView(SectionListView, "hidden"); // hide listview on page load
break;
}
}
ASP.net code
<InsertItemTemplate>
<tr style="">
<td>
<div style="font-size: .8em;">
<asp:FormView ID="SectionFormView" runat="server" DataKeyNames="SectionItemID" DataSourceID="SectionDataSource">
<ItemTemplate>
<asp:Button ID="InsertButton" runat="server" Text="Insert" OnClick="SectionItemButton_Click" Font-Size="1.2em" />
<asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Clear" Font-Size="1.2em" />
<asp:Label ID="SectionItemLabel" runat="server" Text="SectionItem" Font-Bold="true" Font-Size="1.2em" />
<asp:TextBox ID="SectionItemTextBox" runat="server" />
<asp:Label ID="SectionItemSubLabel" runat="server" Text="SectionItem Label" Font-Bold="true" Font-Size="1.2em" />
<asp:TextBox ID="SectionItemLabelTextBox" runat="server" />
</ItemTemplate>
</asp:FormView>
</div>
</td>
</tr>
</InsertItemTemplate>
<ItemTemplate>
You got that error, because the listview was not binded yet, so i think the best way would be to do all this on the ItemDataBound event. You would find the FormView like:
if (e.Item.ItemType == ListViewItemType.DataItem)
{
FormView SFormView= (FormView)e.Item.FindControl("SectionFormView");
if (SFormView!= null)
{
//code here
}
}
You could use this code to find about anything. I used it before to find Literals that I created in code behind. Use this code to find your FormView
private readonly List<FormView> _foundControls = new List<FormView>();
public IEnumerable<FormView> FoundControls
{
get { return _foundControls; }
}
public void FindChildControlsRecursive(Control control)
{
foreach (Control childControl in control.Controls)
{
if (childControl.GetType() == typeof(FormView))
{
_foundControls.Add((FormView)childControl);
}
else
{
FindChildControlsRecursive(childControl);
}
}
}
FindChildControlsRecursive(<Insert relevent Code Here: Whatever element you want to search inside of like your listView, find that using FindControl>);
FormView[] strControl = new FormView[200];
strControl = FoundControls.ToArray();
foreach (FormView i in strControl)
{
if (i.ID.Equals("< insert controlId of your FormView>"))
{
// do something when you find it
}
}
From a listview control, when checkboxes are checked and a button is clicked from outside the listview, I need to be able to delete the items that have been checked. Here's the listview:
EDIT
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack) return;
var notes = (from n in db.Notes
select n).OrderBy(n => n.FiscalYear).ThenBy(n => n.Period);
notesListView.DataSource = notes;
notesListView.DataBind();
}
<asp:ListView ID="notesListView" ItemPlaceholderID="itemPlaceholder" runat="server">
<LayoutTemplate>
<div>
<asp:PlaceHolder ID="itemPlaceholder" runat="server"></asp:PlaceHolder>
</div>
</LayoutTemplate>
<ItemTemplate>
<asp:CheckBox ID="checkNote" runat="server" />
<div><%# Eval("Period") %></div>
<div><%# Eval("FiscalYear") %></div>
<div><%# Eval("Account") %></div>
<div class="wrap"><%# Eval("Description") %></div>
</ItemTemplate>
<EmptyDataTemplate>
<div>No notes have been submitted.</div>
</EmptyDataTemplate>
</asp:ListView>
<br />
<asp:Button ID="deleteNotes" CssClass="deleteButton" Text="Delete Notes" runat="server" OnClick="deleteNotes_Click" />
Here's the code behind:
protected void deleteNotes_Click(object sender, EventArgs e)
{
foreach (ListViewItem item in notesListView.Items)
{
// I know this is wrong, just not sure what to do
if (notesListView.SelectedIndex >= 0)
{
CheckBox ck = (CheckBox)item.FindControl("checkNote");
if (ck.Checked)
{
var index = item.DataItemIndex; // the item row selected by the checkbox
// db is the datacontext
db.Notes.DeleteOnSubmit(index);
db.SubmitChanges();
}
}
else
{
errorMessage.Text = "* Error: Nothing was deleted.";
}
}
}
You need to find the object before deleting it. To do so, I would add a hiddenfield to store NoteID like this:
<asp:HiddenField ID="hdnId" Value='<%#Eval("Id")%>' runat="server" />
<asp:CheckBox ID="checkNote" runat="server" />
... ... ...
And in my code I am finding the note by ID and deleting that note (You may use any other unique field instead of ID). My code may look like this:
... ... ...
int id = 0;
var hdnId = item.FindControl("hdnId") as HiddenField;
CheckBox ck = (CheckBox)item.FindControl("checkNote");
//I would check null for ck
if (ck != null && ck.Checked && hdnId != null && int.TryParse(hdnId.Value, out id)
{
// db is the datacontext
Note note = db.Notes.Single( c => c.Id== id );
db.Notes.DeleteOnSubmit(note );
db.SubmitChanges();
}
I think I have figured out what happens with this program.
This is part of the markup.
<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
</asp:ToolkitScriptManager>
<asp:UpdatePanel ID="upGrid" runat="server">
<ContentTemplate>
<asp:GridView ID="dgvPeliculas" runat="server" AllowPaging="true" PagerStyle-CssClass="pgr"
CssClass="mGrid" EmptyDataText="No hay más películas" OnPageIndexChanging="dgvPeliculas_PageIndexChanging1"
EnableSortingAndPagingCallbacks="true" OnRowDataBound="dgvPeliculas_RowDataBound">
</asp:GridView>
</ContentTemplate>
</asp:UpdatePanel>
<table class="LogIn">
<tr>
<td>
<asp:UpdatePanel ID="upAlquiler" runat="server">
<ContentTemplate>
<asp:Button ID="btnAlquilar" runat="server" Text="Alquilar" CssClass="AdminButtons"
OnClick="btnAlquilar_Click" OnClientClick="javascript: Click_Alquilar(); return false" />
</ContentTemplate>
</asp:UpdatePanel>
</td>
<td>
<asp:Button ID="btnNuevo" runat="server" Text="Nuevo" CssClass="AdminButtons" OnClick="btnNuevo_Click"
OnClientClick="javascript: Click_Nuevo(); return false" />
</td>
<td>
<asp:Button ID="btnEditar" runat="server" Text="Editar" CssClass="AdminButtons" OnClick="btnEditar_Click"
OnClientClick="javascript: Click_Editar(); return false" />
</td>
<td>
<asp:Button ID="btnBorrar" runat="server" Text="Borrar" OnClientClick="javascript: Click_Borrar(); return false"
CssClass="AdminButtons" />
</td>
</tr>
</table>
I have coded it in such a way that the buttons modify it when a row is selected. The rows are selected by changing the "onclick" event (changed during the RowDataBound function), and a Javascript function.
This is how I change the code behind:
protected void dgvPeliculas_RowDataBound(object sender, GridViewRowEventArgs e)
{
dgvPeliculas.CssClass = "mGrid";
if (e.Row.RowType == DataControlRowType.DataRow)
{
string rowID = String.Empty;
rowID = "row" + e.Row.RowIndex;
e.Row.Attributes.Add("id", rowID);
e.Row.Attributes.Add("onclick", "onClick(" + "'" + rowID + "'" + ")");
e.Row.Attributes.Add("onmouseover", "this.style.cursor='pointer'; this.style.backgroundColor = '#B0C5BB';");
e.Row.Attributes.Add("onmouseout", "this.style.backgroundColor = '';");
}
}
This is the JavaScript function:
/
function onClick(rowID)
{
//Si no hay ninguna seleccionada
if (selected == '') {
index = rowID;
selected = document.getElementById(rowID);
selected.onmouseover = '';
selected.onmouseout = '';
selected.style.backgroundColor = 'yellow';
}
else {
//Si se deselecciona
if (selected == document.getElementById(rowID)) {
selected.onmouseover = onmouseover;
selected.onmouseout = onmouseout;
selected.style.backgroundColor = '';
selected = '';
index = '';
}
//Deseleccionar el actual y seleccionar el nuevo
else {
selected.onmouseover = onmouseover;
selected.onmouseout = onmouseout;
selected.style.backgroundColor = '';
index = rowID;
selected = document.getElementById(rowID);
selected.onmouseover = '';
selected.onmouseout = '';
selected.style.backgroundColor = 'yellow';
}
}
}
The New button shows a ModalPopupExtender, and from there it calls a JavaScript function to validate its contents, and then does a postback to code behind to check and update the database. It also appends the register on the Grid, obviously.
The Edit button and the rest through the exception. The Edit function is particular, because its functionality is similar to that of the New button. It shows the ModalPopupExtender, goes to the JavaScript function, does the postback, to the database and updates. But this one needs to have one of the rows in the Grid selected (otherwise, there's nothing to be edited). I believe this is the reason why it throws the "Invalid Postback or Callback" exception. The same condition applies to the other buttons, and all of them throw the same exception. All, except New, which doesn't need to have a row selected.
Do you think this is the reason why I'm having this problem? And if so, how can I fix it?
Sorry if you consider this a repost of one of my previous threads, but I haven't been able to fix the problem, and I think this gives me a new clue that I can't work out neither.
Thanks.
I used repeater in asp.net. My problem is don't know how to hide a fields in repeater. There is a regular price and now price if regular price is equal to zero it will hide the fields and if not it will show the value of the regular price. i hope you can help on this.
here my code in asp:
<a href="<%=Utility.GetSiteRoot() %>/BookInfo.aspx?SKU=<%# Utility.SKUMask(Eval("lb_sku").ToString()) %>">
<img width="150px" src='<%# Eval("lb_picturepath")%>'>
</td>
<td valign="top">
<asp:Label ID="lb_titleLabel" runat="server" CssClass="center-head" Text='<%# Eval("lb_title") %>' />
<p><asp:Label ID="lb_descriptionLabel" runat="server" Text='<%# Eval("lb_description") %>' /></p>
<div class="price"><%# "Price: " + decimal.Round((decimal)Eval("lb_sellingprice"),2)%></div>
</td>
</tr>
<tr>
<td></td>
<td>
<a class="addtocart" href="<%=Utility.GetSiteRoot() %>/AddToCart.aspx?SKU=<%# Utility.SKUMask(Eval("lb_sku").ToString()) %>" >Add To Cart</a>
<a href="<%=Utility.GetSiteRoot() %>/BookInfo.aspx?SKU=<%# Utility.SKUMask(Eval("lb_sku").ToString()) %>" class="readmore">
View Details
</a></td>
thanks!
You would need to handle the OnItemDataBound event, and then change the visibility of the control. An example of this is shown below:
ASPX Page
<asp:Repeater ID="MyRepeater" OnItemDataBound="MyRepeater_OnItemDataBound" runat="server">
<ItemTemplate>
<asp:Label ID="RegularPriceLabel" runat="server" />
<br/>
<asp:Label ID="BuyNowPriceLabel" runat="server" />
</ItemTemplate>
</asp:Repeater>
Code Behind
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
MyRepeater.DataSource = GetDataSource();
MyRepeater.DataBind();
}
}
protected void MyRepeater_OnItemDataBound(object sender, RepeaterItemEventArgs e)
{
if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
// This will be your data object
MyEntity o = (MyEntity) e.Item.DataItem;
// Get the labels
Label RegularPriceLabel = (Label) e.Item.FindControl("RegularPriceLabel");
Label BuyNowPriceLabel = (Label) e.Item.FindControl("BuyNowPriceLabel");
// Only show regular price if it is set
RegularPriceLabel.Visible = (o.RegularPrice > 0);
// Populate labels
RegularPriceLabel.Text = o.RegularPrice.ToString();
BuyNowPriceLabel.Text = o.BuyNowPrice.ToString();
}
}
I would take a look at the ItemDataBound event of the Repeater. It will fire for every item in the repeater and allow you to do any code-behind (like hiding labels) more easily.
Edit: For your specific example, since you are formatting the price as well, it may be easier to just call a custom method to to render the price, like so:
ASPX:
<%#RenderPrice((decimal)Eval("lb_sellingprice"))%>
Method:
protected string RenderPrice(decimal price) {
if (price > 0) {
return "Price: $" + decimal.Round(price);
} else {
return string.Empty;
}
}
It's quick-and-dirty but it works.
aspx page:-
<asp:Repeater ID="rptAdd" OnItemCommand="rptAdd_ItemCommand" runat="server">
<ItemTemplate>
<td>
<asp:LinkButton ID="lnkBill" Text="Make Default" runat="server" Visible="true" CommandName="DefaultBill"></asp:LinkButton>
<asp:Label ID="labelBill" Text="Yes" Visible="false" runat="server"></asp:Label>
</td>
</ItemTemplate>
</asp:Repeater>
Code Behind:-
protected void rptAdd_ItemCommand(object source, RepeaterCommandEventArgs e)
{
if (e.CommandName == "DefaultBill")
{
Users objBill = new Users();
objBill.IsDefault = true;
e.Item.FindControl("labelBill").Visible=true;
e.Item.FindControl("lnkBill").Visible = false;
}
}
In code behind intellisense is not detecting "labelBill" and "lnkBill"..what could be wrong ?
Also need to know...that's how u access controls in a repeater ?? like using findControl() ...right ?
[EDIT]
Changed code as follows..still not working...
((Label)e.Item.FindControl("labelBill")).Visible=true;
((LinkButton)e.Item.FindControl("lnkBill")).Visible = false;
Why wont intellisense detect these two IDs??
The problem is that your controls are inside a repeater, the find control wont search recursively. Try this instead.
rptAdd.FindControl("labelBull").Visible = true;