I've a Calendar on my webpage, and during the page_load event I'm setting the webpage to take today's date and load the data for today's date in the Gridview. Paging is allowed in the Gridview.
I also have a Calendar_Selectiondate event and when someone clicks on a date in the calendar, it will show data for that date. The date value is showed in a session variable. In this scenario when I click on the paging hyperlink 2, it will take me to the current day's second page instead of the selected day's second page. I know this is because it's going through the Page_Load event whenever I click on that hyperlink 2 and the date is getting set to Today's date instead of the selected date.
public partial class UKMail_UKMail7Day : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Calendar.SelectedDate = DateTime.Today;
Session["MailDate"] = Calendar.SelectedDate;
UKMail7DayGridView.DataSourceID = "UKMail7DaySelected";
UKMail7DayGridView.DataBind();
//UKMail7DayGridView.DataSourceID = "UKMail7DayAllData";
//UKMail7DayGridView.DataBind();
}
protected void Calendar_SelectionChanged(object sender, EventArgs e)
{
Session["MailDate"] = Calendar.SelectedDate;
UKMail7DayGridView.DataSourceID = "UKMail7DaySelected";
UKMail7DayGridView.DataBind();
}
}
The events in your Page_Load execute no matter what triggers the postback. If you have code that should ONLY happen the FIRST time a page is loaded, put it within an if(!Page.IsPostback) block.
void Page_Load(object sender, EventArgs e)
{
// code that will execute on every postback, button click, etc.
if(!Page.IsPostback)
{
//code that will only execute the first time the page is loaded.
}
}
Strongly recommended reading: (Every ASP.NET developer should know this.) http://msdn.microsoft.com/en-us/library/ms178472.aspx
Edit using your updated code:
public partial class UKMail_UKMail7Day : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if(!Page.IsPostback)
{
Calendar.SelectedDate = DateTime.Today;
Session["MailDate"] = Calendar.SelectedDate;
UKMail7DayGridView.DataSourceID = "UKMail7DaySelected";
UKMail7DayGridView.DataBind();
//UKMail7DayGridView.DataSourceID = "UKMail7DayAllData";
//UKMail7DayGridView.DataBind();
}
}
protected void Calendar_SelectionChanged(object sender, EventArgs e)
{
Session["MailDate"] = Calendar.SelectedDate;
UKMail7DayGridView.DataSourceID = "UKMail7DaySelected";
UKMail7DayGridView.DataBind();
}
}
In the page load event, set this
if(Page.IsPostback)
return;
Do this before any of your other code so it wont be executed on postback. I hope I understood you correctly.
Related
I have a DropDownList and a CheckBox on my web form. After the DropDownList is clicked and this event is posted back to the server. DropDownList_SelectedIndexChanged event is called on the server side. Inside that event handler, I have CheckBox.Checked = true, But I couldn't make the page on the client side to reflect this change (CheckBox.Checked = true). How do I achieve this? Or am I in the wrong direction to use the DropDownList's event handler to update the CheckBox because the page firstly reloads and then DropDownList_SelectedIndexChanged is called?
Page load method:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
this.DropDownList1.Items.Clear();
AddItemsToDropDownList();
}
}
DropDownList selected index changed event handler:
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
var selected = this.DropDownList1.SelectedItem.Text;
CheckBox checkBox = GetCheckBoxToBeSetByText(selected);
checkBox.Checked = true;
}
OK. Found the issue. Actually there is nothing wrong with the code in my original post. But to make a smallest sample when I posted, I removed some "extra" code. The below is the "complete" code (OK, fine, I still removed some code). As you can see, I put the CheckBox into a static Dictionary. Each time the SelectedIndexChanged event handler is called, it's modifying the CheckBox in that static Dictionary, which means it's modifying the CheckBox object created from the last session? (still not clear here) Looks like each time when a postback message is received, a new set of CheckBox objects are created. Bear with me if this is known to everybody here already because I only have two days of experience on this web development thing up to today.
private static Dictionary<Environment, CheckBox> EnvironmentsCheckBoxes;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
EnvironmentsCheckBoxes = new Dictionary<Environment,CheckBox>();
EnvironmentsCheckBoxes.Add(Environment.Dev1, this.Dev1_CheckBox);
EnvironmentsCheckBoxes.Add(Environment.Dev2, this.Dev2_CheckBox);
EnvironmentsCheckBoxes.Add(Environment.QA, this.QA_CheckBox);
EnvironmentsCheckBoxes.Add(Environment.QA2, this.QA2_CheckBox);
EnvironmentsCheckBoxes.Add(Environment.Demo, this.Demo_CheckBox);
EnvironmentsCheckBoxes.Add(Environment.Prod, this.Prod_CheckBox);
EnvironmentsCheckBoxes.Add(Environment.UAT, this.UAT_CheckBox);
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
var selected = this.DropDownList1.SelectedItem.Text;
if (selected == "Dev1")
{
EnvironmentsCheckBoxes[Environment.Dev1].Checked = true;
}
else if (selected == "Dev2")
{
...
}
...
}
I have a form which has a single textbox that sends some data to the database upon hitting enter. Data is displayed below the textbox in a repeater control. Input data is displayed on the form immediately by binding the data to the repeater in the TextChanged event of that textbox.
In the CodeBehind, I am calling BindRepeater method twice, once on every new page load and once on the TextChanged event of the textbox.
How can this be rewritten to call the BindRepeater only once and still achieve the same effect?
protected void Page_Load(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
BindRepeater();
}
}
protected void BindRepeater()
{
// data retrieval
// repeater binding
}
protected void CreateData(string newdata)
{
// data insert
}
protected void TextBox1_TextChanged(object sender, EventArgs e)
{
if (TextBox1.Text != string.Empty)
{
string _newData = TextBox1.Text.Trim();
CreateData(_newData);
BindRepeater();
}
}
Use an event that would be fired after the text changed event to do the binding in. you can now remove it from the page load event.
Time for my daily ASP.NET question.
One of my pages shows all of our customer information from a customer table. I want the user to choose whether to see all customer records, or select a specific record from a list. So, my webpage has two radio buttons (show all customers, show specific customer), a listbox (full of customer names), and a formview control. The problem I'm having is getting the formview to update when I change modes via radio buttons or listbox selection (see code below).
Can anyone provide me with some pointers on how to do what I'm trying to do?
protected void Page_Load(object sender, EventArgs e)
{
UpdatePage ();
}
protected void RadioButtonShowAll_CheckedChanged(object sender, EventArgs e)
{
}
protected void RadioButtonShowSelected_CheckedChanged(object sender, EventArgs e)
{
}
protected void DropDownListCustomers_SelectedIndexChanged(object sender, EventArgs e)
{
RadioButtonShowSelected.Checked = true;
UpdatePage ();
}
protected void UpdatePage ()
{
if (RadioButtonShowAll.Checked)
SqlDataSource1.SelectCommand = "SELECT * FROM [Customer] ORDER BY [Company]";
else
SqlDataSource1.SelectCommand = "SELECT * FROM [Customer] WHERE ([CustomerID] = #CustomerID) ORDER BY [Company]";
FormView1.DataBind();
}
First, you only have the SelectedIndexChanged event wired up... In that case, what happens when you change the drop down box is first, Page_Load() fires--which calls UpdatePage(). Then, the event fires, which calls UpdatePage() again. The second time probably doesn't do what you expect.
The fix is to only call UpdatePage() from Page_Load() the first time the page is loaded, but not from postbacks:
protected void Page_Load(object sender, EventArgs e)
{
if (!this.IsPostBack)
UpdatePage();
}
Your page has to be updated on Client side, for it to show the new data. You'll need to use Javascript or AJAX and have some variable that keeps track of the need to refresh your page, this way you can send a request to update the page to the server when the Formview needs updating.
In my webpage I have two dropdown controls for namely ddlmonth and ddldays ( for month & days)
I write a method for current month in ddlmonth and current day in ddldays and i call that method in page load event it working fien but when i select (in ddlmonth ) different month and different day and insert into database the values inserted in database is current month and current day, actually i select different month and day
This is my code
This is the method for current date display in ddlmonth dropdwon control and ddlday
public void getMonth()
{
ddlmonth.SelectedIndex = DateTime.Now.Month -1;
ddldate.SelectedIndex = DateTime.Now.Day - 1;
}
I call this in page load
protected void Page_Load(object sender, EventArgs e)
{
getMonth();
}
If I call the getMonth method in postback
protected void Page_Load(object sender, EventArgs e)
{
if(!ispostback)
{
getMonth();
}
}
it not displaying the current month and date
without postback it is working
When I select different month and day and insert into database it is taking current month and day
Please help me
You can try to use Request.Form["ddlmonth"] and Request.Form["ddlday"] to retrieve the values.
Sorry if I misunderstood, but to "call the getMonth method in postback", you need check for ispostback = true, not false.
protected void Page_Load(object sender, EventArgs e)
{
if(isPostback)
{
getMonth();
}
}
I think u should use
protected void Page_Load(object sender, EventArgs e)
{
if(!ispostback)
{
getMonth();
}
}
The page is loaded and dropdowns showing Current date and month.
After that you choose different date and month and click some button to save that in database.
In the button event you write the insertion code and if required then there again call getMonth() method to load again the current date and month in the dropdowns. The date u chose in the dropdowns will be saved in DB. If required you call getMonth() method to load current date again as below.
protected void btnSave_Click(object sender, EventArgs e)
{
//-------- insertion code ----------------//
getMonth();
}
i want to creat a web page that uses radiobuttons in a multiple choice quetions, but i want to do is to use a submit button to return the results to the next page with the mark sheet, so can you please help me with that. how to display the mark sheet on the next page using ASP.NET
Use Session state.
For example,
protected void Button1_Click(object sender, EventArgs e)
{
Session["key"] = TextBox1.Text;
Response.Redirect("marksheet.aspx");
}
Code in Page_Load of marksheet.aspx,
protected void Page_Load(object sender, EventArgs e)
{
if (Session["key"] != null)
{
object val = Session["key"];
...
}
}