Aim: To add a session to the ASP button so I can change the CSS value based on a set of rules.
Code so far:
<asp:Button ID="btnMyDetails" runat="server" Text="My Details" CssClass="<%=Session.Item('btnMyDetails').ToString()%>" CausesValidation="False" />
Error:
The above code tries to run the session as text and not a session. I've tried with both " and ' around.
History:
I have a working version where I use lists but would like to remove this extra coding:
<li class="<%=Session.Item("btnMyDetails").ToString()%>"
<asp:Button ID="btnMyDetails" runat="server" Text="All" CssClass="Button" /></li>
Use Following:
<asp:Button ID="btnMyDetails" runat="server" Text="My Details" CssClass='<%#Session["btnMyDetails"].ToString()%>' CausesValidation="False" OnClick="btnMyDetails_Click" />
When you set value for your Session variable at that time don't forget to call DataBind method of Button that you created. if you do not call DataBind method nothing will get assigned.
for example on page_load method you set your session variable to some value,
protected void Page_Load(object sender, EventArgs e)
{
Session["btnMyDetails"] = "firstClass";
btnMyDetails.DataBind();
}
'firstClass' will be assigned as cssClass to your button.
After that if you change value of your session variable then again call DataBind method of that button. Example of Button Click event is given
protected void btnMyDetails_Click(object sender, EventArgs e)
{
Session["btnMyDetails"] = "NewClass";
btnMyDetails.DataBind();
}
Now 'NewClass' will get assigned.
I'd go a few steps to avoid depending on your session that way, tying to directly to a property of a control. At the very least I'd call a property like MyDetailsButtonCssClass in the Page class and put the logic there.
Is there a particular condition that's being changed in session that you could use to determine the class instead of putting the class name directly in session? Otherwise you could find yourself with one logical condition that changes but multiple class names that get stored in session.
Related
I currently have a listview on an ASP.NET webpage that displays "cottage" records from an Access database. The name of each cottage is displayed as a hyperlink so when clicked brings you to another webpage:
<li style="">Name:
<asp:Hyperlink ID="Cottage_NameLabel" NavigateURL="~/Cottage.aspx"
runat="server" Text='<%# Eval("Cottage_Name") %>' />
<br />
This works perfectly fine when selecting a hyperlink. What I want the system to do is to set the value of a publically declared variable (set in a module) to the Cottage_Name of the selected hyperlink. So say if i clicked on a hyperlink that said "cottage1", the public variable is set to "cottage1" and then the navigate URL opens the next webpage.
Would really appreciate it if anyone could help me do this!
Just use a LinkButton instead of a Hyperlink... Catch the click event and do whatever you want...
For instance:
<asp:LinkButton ID="Cottage_NameLabel" runat="server" Text="whatever" onclick="Cottage_NameLabel_Click" />
Then in CodeBehind:
protected void Cottage_NameLabel_Click(object sender, EventArgs e)
{
LinkButton btn = (LinkButton)sender;
Session["MyCottageName"] = btn.Text;
Response.Redirect("Cottage.aspx");
}
In your Cottage.Aspx page you can check the value of the Session variable like this:
protected void Page_Load(object sender, EventArgs e)
{
if (Session["MyCottageName"] != null)
{
string name = (String)Session["MyCottageName"];
...
}
You can pass the name as a querystring variable to the page. If you go this route, you need to make sure you URL encode the cottage name:
<a href='/Cottage.aspx?name=<%# Server.UrlEncode(DataBinder.Eval(Container.DataItem, "Cottage_Name")) %>'><%# Eval("Cottage_Name") %></a>
And then on cottage.aspx you can get the cottage name:
Dim cottageName As String = Request.QueryString("name")
This would be preferable to a button or other postback solution as it removes the need for a postback and then a redirect.
I have this hyperlink called “SEND” in a ASP page called Home and here it is:
<asp:TemplateField>
<ItemTemplate>
<asp:HyperLink ID="HyperLink1" runat="server"
NavigateUrl='<%# Eval("Post_ID", "~/RCA.aspx?Post_ID={0}") %>'
Text="SEND"></asp:HyperLink>
</ItemTemplate>
when the user clicks the hyperlink it goes to another page called RCA and in this page there is a Button and here it is the code:
<asp:Button ID="btnRCA" runat="server" onclick="Button1_Click"
Text="Assign RCA" Width="147px" />
so I want this button to be visible only when clicked the hyperlink in the HOME page. I am planning to have another button or control in the RCA page that will make it invisible when clicked or before someone leaves the page they have to make it invisible the Button by clicking some other control. can someone help me with this? thanks
Use a QueryString parameter.
Home.aspx
//When linked to RCA.aspx from Home.aspx, a parameter called ShowButton=1 is included
//in the URL.
<asp:HyperLink ID="HyperLink1" runat="server"
NavigateUrl='<%# Eval("Post_ID", "~/RCA.aspx?Post_ID={0}&ShowButton=1") %>'
Text="SEND"></asp:HyperLink>
RCA.aspx
//By default, since you want the button to NOT appear for all incoming traffic EXCEPT
//that which came from Home.aspx, the button's Visible property is set to false.
<asp:Button ID="btnRCA" runat="server" onclick="Button1_Click"
Text="Assign RCA" Width="147px" Visible="false" />
RCA.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
//If the querystring has a parameter called ShowButton and it's equal to "1",
//then set the button to Visible = true.
//Else, do nothing, keeping the button in it's default, Visible=false state.
//By putting this in an "IsPostback == false" check, you can guarantee that this will
//only happen on first page_load, and won't be triggered again even if you do other
//actions in the page that cause Postback
//For example, if you don't use this !IsPostback check, and you end up creating some
//new function that causes the button to be hidden again, but then you make a
//selection from a dropdown list that causes postback, you will trigger the call to
//make the button Visible again, even though that's probably what you don't want at
//this point, since your other new function set it to Visible = false.
if (!IsPostback)
{
if (Request.QueryString["ShowButton"] == "1")
{
RCAbtn.Visible = true;
}
if (Request.QueryString["Post_ID"] != null)
{
//do whatever you need to with the post ID
}
}
}
SomeOtherPage.aspx.cs
Response.Redirect("RCA.aspx?Post_ID=1234"); //button will be invisible
And then let's say later that you want to re-direct from some other page and have the button be visible, like the redirect from Home:
Response.Redirect("RCA.aspx?Post_ID=1234&ShowButton=1"); //button will be visible
If you don't like cluttering up your URL or you feel that it looks tacky to have what you are doing so plainly available to the user's eyes, you don't necessarily need to use "ShowButton". You could say ?Post_ID=1234&fkai3jfkjhsadf=1, and then check your query string for "fkai3jfkjhsadf". I like to do that sometimes because then from the users point of view, it makes me look like I'm doing something really technical and encrypted, and not just passing around a bunch of basic instructions in plain English :) Downside there is you need keep track of your own query string parameters.
Edit:
If you want to get the URL with only the Post_ID and nothing else, you can do this:
string currenturl = Request.Url.ToString(); //get the current URL
string urlToSend = currenturl.Substring(0, currenturl.IndexOf("?")); //cut off the QueryString entirely
urlToSend += "?Post_ID=" + Request.QueryString["Post_ID"]; //re-append the Post_ID
Be aware that your call to Substring will cause an exception if the URL doesn't have a QueryString, so please patch that up in whatever way works best for you (try/catch, etc.).
After that, you should just be able to use the "urlToSend" string in your mailMessage.Body.
on your second page in your page_load, try this:
protected void Page_Load(object sender, EventArgs e)
{
if (Request.QueryString["Post_ID"] != null)
{
btnRca.Visible = true;
}
}
I don't know how you want to handle the visibility of this button in other cases, but this should answer your particular question.
I have a Results.aspx page that displays the resulting records queried using a SqlDataSource object via a ListView. I want to add a "View" button that will appear next to each record, and when clicked will take me to a separate page that will display details about that record. How do I accomplish this?
Edit
I have tried what you said, citronas and here's what I've come up with:
<td>
<asp:CheckBox ID="CheckBox1" runat="server" />
</td>
<td>
<asp:LinkButton ID="LinkButton1" runat="server" CommandName="ViewButtonClick" CommandArgument='<%# Eval("ServiceId") %>'>View</asp:LinkButton>
</td>
And here is the method that I want to be called:
protected void ViewButtonClick(object sender, CommandEventArgs e)
{
var serviceId = Convert.ToInt32(e.CommandArgument);
ServiceToView = DataAccessLayer.Service.Select(new Service { ServiceId = serviceId });
Server.Transfer("~/ViewService.aspx");
}
Unfortunately nothing actually happens...am I missing something?
Edit -- Fixed
I was missing something! I had CommandName equal to my method name instead of OnCommand. I took out CommandName, kept the argument bit and replaced CommandName with OnCommand. Everything works now, but what would I ever need CommandName for?
You can add a LinkButton into the ItemTemplate of the ListView.
Bind the value that identifies each record to the CommandArgument of the LinkButton.
Subscribe to the Command-Event of the LinkButton. There you have access to CommandEventArgs.CommandArgument
What you wound up doing worked Storm. I decided to go with Citronas' suggestion and share my answer.
FIRST:
On the aspx I added a LinkButton to my ItemTemplate with my own CommandName and CommandArgument. I passed my item's ID as a CommandArgument so I could later use it inside my sub.
<asp:LinkButton ID="lnkBtnAnswers" runat="server" CommandName="Answers"
CommandArgument='<%# Eval("ID")%>'>Answers</asp:LinkButton>
SECOND:
On the codebehind I created a sub that would be called whenever the user conducted an action. As Citronas mentioned normally you use "Select", "Add", "Edit", or "Delete" here. I decided to create "answers".
Note: Handles MyControl.ItemCommand is very important here as it is what subscribes you to the command event.
Protected Sub lvQuestions_Command(sender As Object, e As CommandEventArgs) Handles lvQuestions.ItemCommand
If e.CommandName.ToLower() = "answers" Then
hfSelectedQuestionID.Value = e.CommandArgument
End If
End Sub
Done! Now since every command goes through the new sub, it is important to check for the right commandName so you can conduct the appropriate action. Don't forget to use the CommandArgument to your advantage.
I have an application that I am currently writing that works by iterating through nodes, and then updating the page with the information of the current node. I have an UpdatePanel in the page which contains a label, textbox, and a button. The label lists the currently available children of the current node, the user enters in which child they want to go to into the textbox, and then hits the submit button. I set the new value of the node in the submit button's event handler.
Here's my problem: Every time I enter in which node I want to navigate to, the object resets its value to the value it was initially initialized to. I have even put this same code into a Windows Form to validate that it's working correctly to iterate through my tree, and it works as it should, so I know my problem is AJAX-related.
This is the first app that I have written using AJAX, so I am still in the process of learning how it works. Any help would be greatly appreciated. I have Googled and searched SO through and through.
Here is the HTML:
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager" runat="server"></asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:Label ID="question" runat="server" Text=""></asp:Label>
<br />
<asp:TextBox ID="answer" runat="server"></asp:TextBox>
<br />
<asp:Button ID="Submit" runat="server" Text="Submit" onclick="Submit_Click" />
</ContentTemplate>
</asp:UpdatePanel>
</form>
And the C#:
protected void Submit_Click(object sender, EventArgs e)
{
int ans = int.Parse(answer.Text);
if (!current.ChildIDs.Contains(ans))
{
return;
}
current = tree.Node(ans);
question.Text = current.Question;
}
current is the current node, which has a public ArrayList of all of its children's IDs. tree is the NodeTree I have; calling Node just returns the new node. Both current and Tree get initialized in the Page_Load event, and that only fires once (when the page is first loaded).
It's really pretty simply code; I'm just having difficulty understanding why the AJAX isn't working correctly.
I have even put this same code into a
Windows Form to validate that it's
working correctly to iterate through
my tree, and it works as it should, so
I know my problem is AJAX-related.
It sounds like you're expecting ASP.NET to remember what the object current is between requests, since that's how Windows forms applications work.
Web applications are stateless - after each request, ASP.NET discards all your variables. To access the variable during a subsequent request, you have to either:
1) Send enough data with the request to reconstruct the variable. You can do this using a querystring parameter or an HTML form value (the hidden fields another response mentioned).
2) Save the variables in a Session store (which can be in-memory or backed by a database).
3) Store the value in a coookie.
Of these three, it's easiest to show you how to use Session, given what you've shared in your question. However, beware: session has its risks - by default, ASP.NET session objects are stored in-memory, and it's a potential security hazard. But here's how you should be able to get your application to work.
// In your Page_Load code that initializes your 'current' variable
// When the user first requests the page, create a new Node
if (! this.IsPostBack)
{
Node current = new Node(); //
Session("currentNode") = current;
}
// When the user clicks a button on the page (posts), use the
// node in session instead
else
{
current = Session("currentNode");
}
When you update non-form elements in the browser (labels, literals, etc.), .NET is unable to see any of the changes you've made.
Try adding a hidden input for each label that records the new value. Then within the method you have wired up to the button's OnClick event, do something like this:
myLabel.Text = myHiddenInput.value;
I think you just need to tell the updatepanel to update itself. Try this:
protected void Submit_Click(object sender, EventArgs e)
{
int ans = int.Parse(answer.Text);
if (!current.ChildIDs.Contains(ans))
{
return;
}
current = tree.Node(ans);
question.Text = current.Question;
UpdatePanel.Update();
}
I have a webform with two custom validators:
One to validate that a string is a date. I don’t care what format, so long as it’s parseable.
Another to ensure that one date is equal to or greater than another. I just couldn’t get the compare validator to play nice with any date format.
<asp:TextBox ID="txtResourceStartDate" runat="server"
CssClass="textBox mandatory dateField" />
<asp:CustomValidator ID="valResourceStartDateIsDate" runat="server"
ControlToValidate="txtResourceStartDate" Display="None"
ErrorMessage="Start date must be a valid date"
OnServerValidate="Date_ServerValidate" />
<asp:TextBox ID="txtResourceEndDate" runat="server"
CssClass="textBox mandatory dateField" />
<asp:CustomValidator ID="valResourceEndDateIsDate" runat="server"
ControlToValidate="txtResourceEndDate" Display="None"
ErrorMessage="End date must be a valid date"
OnServerValidate="Date_ServerValidate" />
<asp:CustomValidator Display="None" Text="" ID="valForStartEndDate" runat="server"
OnServerValidate="ValidateStartEndDate"
ErrorMessage="Last day must be greater than or equal to first day" />
protected void Date_ServerValidate(object source, ServerValidateEventArgs args)
{
DateTime outDate;
args.IsValid = DateTime.TryParse(args.Value, out outDate);
}
protected void ValidateStartEndDate(object sender, ServerValidateEventArgs e)
{
e.IsValid = DateTime.Parse(txtResourceEndDate.Text) >=
DateTime.Parse(txtResourceStartDate.Text);
}
The problem is that the ValidateStartEndDate validator is firing before the Date_ServerValidate validator, so if the date is not valid, a format exception is thrown on DateTime.Parse. Obviously this validator could check for a valid date before parsing, but I’d really prefer to have a discrete validator with an appropriate message.
So the question is this: what determines the sequence with which the validators fire? Unless I’m missing something, this is not declared at the tag level.
You can't count on a certain sequence the validators will fire and also you shouldnt. You have to make sure for yourself that the order is irrelevant.
So you could
check for the valid date
simultaneously with the
Equal-Greater-Check.
First Call your IsDate-Validator's Validate()-Function and then check if it IsValid
All validators are added to the Page.Validators collection and validation runs through this collection in order. If your logic really should rely on this order: change the order of the validators in the ASPX-Page
Some interesting infos about Page-Validation: http://msdn.microsoft.com/en-us/library/aa479045.aspx
Validation control execution order is determined by the order of the controls in the ValidatorCollection returned by Page.Validators. This order is, in turn, determined by the order of the validation controls in the markup, with some exceptions (e.g. validators within data-bound controls will get added to the collection later, and so will be at the end).
If you set CausesValidation=false on your button and then trigger validation manually with Page.Validate, you can use the Add and Remove methods on the ValidatorCollection to change the execution order:
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack) {
// move myValidator to the very end, so it executes last
Validators.Remove(myValidator);
Validators.Add(myValidator);
}
}
Then, later on in the triggering control:
protected void myButton_Click(object sender, EventArgs e)
{
Page.Validate();
if (!Page.IsValid) { return; }
// validation passed, proceed...
}
Disclaimer: all of this is empirical, I haven't found MSDN docs to back it up, but it seems to work.