I have made a page which has a checklist having checkboxes with values. I have a button which should send values to a PostBackUrl page, which is not code behind file, but a postback page, called TestPage.aspx.
Now if i have any text field or list box or checklist group, I want to access its values on that page, which is redirected using PostBackUrl.
In code behind, if i do something like FirstName.Text, i receive its value. Can i get something like that on PostBackedPage?
Thanks
Yes you can - you can access named form / post variables from a page using the Request.Form collection:
protected void Page_Load(object sender, EventArgs e)
{
string firstName = Request.Form["FirstName"];
}
protected void Page_Load(object sender, EventArgs e)
{
TextBox myTxt = (TextBox)Page.PreviousPage.FindControl("previousPageTextBoxName");
currentPageTextBox.text = myTxt.Text;
}
Related
Hi I'm trying to save the values from the request.form after post back. I've tried to use viewstate on the input string but the page_load keeps regenerating the request.form
string TID = null;
Protected void Page_Load(object sender, EventArgs e)
{
if (TID == null)
{
TID= Request.Form ["totalID"];
}
Label1.Text = TID;
}
protected void Button2_Click (object sender, EventArgs e)
{
Label1.Text = TID;
}
Most asp.net controls have a text property, so if yours is a TextBox and you named it textBoxTotalID, then you can just get the value entered using this.textBoxTotalID.Text.
Instead of totalID, use the name of the element not the Id. The name is used for posting information to the server. And also make sure you have specified a name in your view for the element whose value you need on post.
In addition to that, ask yourself this question: Do you need to do that even when the user requests the page or only when the form is submitted? I am sure your answer is only when form is submitted. In that case, do it only when IsPostBack is true.
Try adding a check to the IsPostBack property.
if (IsPostBack)
{
//Set Values here
}
This is set to true when the page is responding to a post back from a form submit or perhaps a control event being fired.
I'm wondering what is my issue on passing a variable from page to page using asp.net session.
I've stripped the code down to just one text box to see whats going on. I'm just trying to take the value of a text box and display it on a confirmation page. When the button is clicked it transfers me to the second page but there label is blank. Yes my post back url is pointing to the second page.
Here is the button click:
protected void submit_Click(object sender, EventArgs e)
{
string name = txtFirstName.Text.Trim();
Session["name"] = name;
}
Here is the page load of the second page:
protected void Page_Load(object sender, EventArgs e)
{
lblName.Text = (string)(Session["name"]);
}
Unless I've been looking at this to long and missed something. I've already read "How to: Read Values from Session State" from MSDN.
You say that you've set the PostBackUrl to your second page. If you're going to do it that way, you need to use Page.PreviousPage to get access to your textbox. But this is the easiest way:
Firstly, leave the PostBackUrl alone. Setting the PostBackUrl to your second page means that you're telling the SECOND PAGE to handle your button click, not the first page. Hence, your session variable never gets set, and is null when you try to pull it.
This should work for ya.
And yes, you can also do this with a QueryString, but if its something that you don't want the user to see/edit, then a Session variable is better.
protected void submit_Click(object sender, EventArgs e)
{
string name = txtFirstName.Text.Trim();
Session["name"] = name;
Response.Redirect("PageTwo.aspx");
}
Then in the second page (You don't REALLY need the ToString()):
protected void Page_Load(object sender, EventArgs e)
{
if (Session["name"] != null)
{
lblName.Text = Session["name"].ToString();
}
}
EDIT -- Make sure that your button click actually gets fired. Someone can correct me wrong on this, as I do most of my work in VB.NET, not C#. But if you don't specify the OnClick value, your function won't get called.
<asp:Button ID="Button1" runat="server" Text="Click Me!" OnClick="submit_Click" />
The code you have posted looks fine, so your problem is probably with setup.
Check this link ASP.NET Session State Overview and pay particular attention to the sections on Cookieless SessionIDs and Configuring Session State.
I don't think you added the session. This is how I have done mine.
First Page
protected void btnView_Click(object sender, EventArgs e)
{
foreach (ListItem li in lbxCheckDates.Items)
{
if (li.Selected == true)
{
lblMessage.Text = "";
string checkDate = lbxCheckDates.SelectedItem.Text;
Session.Add("CheckDates", checkDate);
Page.ClientScript.RegisterStartupScript(
this.GetType(), "OpenWindow", "window.open('Paystub.aspx','_newtab');", true);
}
}
}
Second Page
protected void Page_Load(object sender, EventArgs e)
{
string checkDate = (string)(Session["CheckDates"]);
//I use checkDate in sql to populate a report viewer
}
So with yours, I think you need..
protected void submit_Click(object sender, EventArgs e)
{
string name = txtFirstName.Text.Trim();
Session.Add("Name", name);
}
I think what you have in the second page should work, but if it doesn't, add ToString() to it like..
lblName.Text = (string)(Session["name"]).ToString();
Let me know if this helps!
Are you doing a redirect after setting the session variable on the first page, if so you it will not work correctly (unless you know the trick). Checkout this article on making it work. Basically, the way to make this work is to the overload redirect method.
Response.Redirect("~/newpage.aspx", false);
The false parameter prevents .net from terminate processing on the existing page (that actually writes out the session state)
For Second Page
protected void Page_Load(object sender, EventArgs e)
{
if (Session["value"] != null)
{
Label1.Text = Session["value"].ToString();
}
else
{
Label1.Text = "Sorry,Please enter the value ";
}
}
You can use Server.Transfer() instead of Response.Redirect()
For first page, use this:
protected void Button1_Click(object sender, EventArgs e)
{
string value = TextBox1.Text;
Session["value"] = value;
Response.Redirect("~/Sessionpage.aspx");
}
I have created a dropdownlist in my webpage which is outside the gridview and I have added automatic refresh. My problem is that I`m unable to retain the selected value in dropdownlist after the refresh. It goes to the default settings in the dropdown. Please help.
Thanks a lot for replying..
part of my code goes this way....
page_load(...)
{
Refresh
if(!IsPostBack)
{
//calling my function which includes databind..
myfunction();
}
}
i tried the same code as you people suggested but its not working..
even now after refresh, the default values appear in dropdownlist
You probably need to implement something like this in your page_load handler:
if (IsPostback) return;
//here populate the dropdown
Let me guess your Page_Load:
protected void Page_Load(object sender, EventArgs e)
{
DataBindGridView(); // loads the datasource of the grid and calls gridView1.DataBind();
DataBindDropDown(); // loads the datasource of the dropdown and calls dropDown1.DataBind();
}
Do not reload all on every postback, just if !(IsPostBack):
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
DataBindGridView();
DataBindDropDown();
}
}
If you need to refresh your GridView don't use Page_Load but the appropriate event handler. If you use an ASP.NET Timer to reload your page periodically to refresh the grid, use it's Tick event.
protected void GridRefreshTimer_Tick(object sender, EventArgs e)
{
DataBindGridView();
}
I have a table with all the objects I have in my db. I load them in my Page_Load function. I have a text field and a button that when clicking the button, I want the handler of that click to put a new object with the name written in the text field in the db.
Now, I want that what happens after the click is that the page loads again with the new item in the table. The problem is that the button event handler is run after the Page_Load function.
A solution to this would be to use IsPostBack in the Page_Load or use the pre load function. A problem is that if I would have 3 different buttons, I would have to differ between them there instead of having 3 different convenient functions.
Any solutions that don't have this problem?
Code:
protected void Page_Load(object sender, EventArgs e)
{
if (Session["userId"] == null)
Response.Redirect("Login.aspx");
// LOAD DATA FROM DB
}
protected void CreateObject(object sender, EventArgs e)
{
// SAVE THE NEW OBJECT
}
Maybe you should try loading your data during PreRender instead of Load
protected void Page_Load(object sender, EventArgs e)
{
this.PreRender += Page_PreRender
if (Session["userId"] == null)
Response.Redirect("Login.aspx");
}
protected bool reloadNeeded {get; set;}
protected void CreateObject(object sender, EventArgs e)
{
// SAVE THE NEW OBJECT
reloadNeeded = true;
}
protected void Page_PreRender(object sender, EventArgs e)
{
if(reloadNeeded || !IsPostBack)
// LOAD DATA FROM DB
}
You can check the event target and do what you need then:
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
{
string eventTarget = Page.Request.Params["__EVENTTARGET"];
if(whatever)
{
//do your logic here
}
}
}
Get control name in Page_Load event which make the post back
Use the Page_PreRenderComplete event to retrieve your table. That way your page will always have the most recent data available after all user events have fired.
Why don't you move what you have in the click event into a new method. Then call that method as the first line in your page load?
An old question but I faced the same problem in my C#/ASP.NET Website with master/content pages: a click on a link on the master page should change a query parameter for a gridview on the content page. As you stated the button click event is handled after Page_Load. But it is handled before Page_LoadComplete (see the information about ASP.NET Page Life Cycle), so you can change the page content there.
In my case I solved the problem by setting a session variable in the click event in the master page, getting this variable in the Page_LoadComplete event in the content page and doing databind based on that.
Master page:
<asp:LinkButton ID="Btn1" runat="server" OnCommand="LinkCommand" CommandArgument="1" >Action 1</asp:LinkButton>
<asp:LinkButton ID="Btn2" runat="server" OnCommand="LinkCommand" CommandArgument="2" >Action 2</asp:LinkButton>
protected void LinkCommand(object sender, CommandEventArgs e)
{
HttpContext.Current.Session["BindInfo", e.CommandArgument.ToString());
}
Content page:
protected void Page_LoadComplete(object sender, EventArgs e)
{
string BindInfo = HttpContext.Current.Session["BindInfo"].ToString();
YourBindDataFunction(BindInfo);
}
I am working on an aspx page in VS 2005. I have code like this,
int RepID = 0;
protected void Page_Load(object sender, Eventargs e)
{
if(!Page.Ispostback)
{
get value from database and display it in textbox;
}
else
{
}
}
protected void Save_OnClick(object sender, Eventargs e)
{
Update Database with modified textbox Text ;
Response.Redirect(//To the same page);
}
After the Response.Redirect, i was looking for the page to refresh and get the modified value from database. Instead, it uses the else loop in Page_load and displays the old value because it doesn't go into the if loop as it is the Postback. How can i display from database after the response.redirect is used. I know i am missing a logic but i am not sure what? Thanks alott guys..
Delete
Response.Redirect(//to same page);
Your Save button click should post back to the same page it is on.