ASP.NET

Re: How to use ASP.Net with Javascript? [modified]

20-Nov-07 23:45

Hi guys,

I have a problem here that I have been unsucessful at solving.

I have a form for user to fill in.

On button click, I perform a series of validations.

Only when the validations pass, I open up a confirm box using javascript.

When the user clicks "OK" I proceed to save the information.
When the user click "Cancel" I refrain from saving the information.

In pseudo code its like this:

btnSave_Click(object sender, EventArgs e)
{
string status= ValidateData();

if(status=="OK")
{
//bring out the confirm box in javascript
ClientScript.RegisterStartupScript(this.GetType(), "ConfirmationPopUp", "getMessage('" + mess.ToString() + "')");
if(userClickOk=="OK")
{
SaveData();
}
}
}

I finally understand that i need a postback from the confirm popup to finally run the SaveData();

So in my java script i try to save the answer in a HiddenField and then on post back check the reply and run SaveData() if the answer is yes.

my Javascript goes like this:

function getMessage(a)
{
var ans;
ans=window.confirm(a);
//ans=;
//alert (ans);
if (ans==true)
{
this.ctl00_ContentPlaceHolder1_HiddenField1.value='Yes';
__doPostBack("","");

}
else
{
this.ctl00_ContentPlaceHolder1_HiddenField1.value='No';
__doPostBack("","");
}
}

However when i try to save the answer in the HiddenField1. I get error that says
this.ctl00_ContentPlaceHolder1_HiddenField1 is null or not an object.

What is wrong? here? I have also tried to save in a session variable which is also not possible?

Please advise how i can achieve this? Is this the right way to do it?

Thanks so much.

Sun Rays20-Nov-07 23:49

Sun Rays

20-Nov-07 23:49

blooper02 wrote:
this.ctl00_ContentPlaceHolder1_HiddenField1.value='No';

Hi,
u can not do like this.
Try this.

var MyHDN = Document.GetelementById("Give hidden field's clientID");<br />
MyHDN.value = "No";

-- modified at 0:19 Thursday 22nd November, 2007

Thanks,
Sun Rays

Rate this post if you like answer.

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J4amieC21-Nov-07 0:14

J4amieC

21-Nov-07 0:14

Sun Rays wrote:
var MyHDN = Documetn.GetelementByID("Give hidden field's clientID");
MyHDN.value = "No";

wow. That couldnt get more wrong if it tried.

JS is case sensitive. So Documetn[sic] should be document and GetelementByID[sic] would be getElementById.

blooper0221-Nov-07 16:02

21-Nov-07 16:02

It works!

Thanks guys....

My old method this.ctl00_ContentPlaceHolder1_HiddenField1.value='Yes';

works when i created a new webpage but my current project which had a masterpage, it does not work.....

thanks thanks

John-ph20-Nov-07 23:56

20-Nov-07 23:56

You don't have to neccessarily do a PostBack for a confirm message. What is wrong in doing the other way round. prompt a Javascript Confirm Message first and If it's Ok, then do a PostBack for the neccessary server-side validation and saving of Data. If validation fails then Alert a error message otherwise Save the data. I guess this is the correct sequence that will solve the problem and minimize the server round trip as well.

- Regards -
JON

Life is not measured by the amount of breaths we take, but by the moments that take our breath away.

blooper0221-Nov-07 14:14

21-Nov-07 14:14

Thanks to Sunray and Jamie for the advise Smile | :)

JON,

My server side validation validates to make sure he do not key in rubbish.

I intend to put most of the information that the user key in the confirm box for him to do final check.

When he clicks OK then I save.

What I worry is that the users may claim that if my system so smart to detect their rubbish data, why pop-up and ask them to confirm in the first place?

Do you or others in the developement field face this problem?

Thanks

John-ph21-Nov-07 19:49

21-Nov-07 19:49

blooper02 wrote:
Do you or others in the developement field face this problem?

This is not a problem. Actually we are discussing about which is the right way to do such a thing. my point here is it's unnecessary to have 2 server-round trips to save the data.

- Regards -
JON

Life is not measured by the amount of breaths we take, but by the moments that take our breath away.

blooper0221-Nov-07 21:19

21-Nov-07 21:19

Hi Jon,

I feel that your advice is correct.

Therefore I tried to call the confirm box at OnClientClick.

My Server Validation still runs and triggers fine. But my Validation controls like regular expressions validator did not fire. You know why?

thanks

John-ph21-Nov-07 23:10

21-Nov-07 23:10

Check Whether the CausesValidation Property of the Button Control is set to True

- Regards -
JON

Life is not measured by the amount of breaths we take, but by the moments that take our breath away.

blooper0221-Nov-07 23:28

21-Nov-07 23:28

Hi Jon,

Yes it is set to true....

But it just does not fire...

Any other possibilities?

John-ph21-Nov-07 23:49

21-Nov-07 23:49

Are you calling any JavaScript function on the Button Click? If yes then it will skip the script validation of the validation Controls. One Alternate to this problem to add the following Code at the end of JavaScript function which you have written.

if (typeof(Page_ClientValidate) == 'function'){ <br />
 Page_ClientValidate();<br />
 return true;<br />
}

This will call the JavaScript Validation code generated for the Validation Controls.

- Regards -
JON

Life is not measured by the amount of breaths we take, but by the moments that take our breath away.

blooper0222-Nov-07 16:07

22-Nov-07 16:07

Hi Jon,

I am putting the code as

return confirm('Do you want to confirm this application?');

in the onclientclick property as in the visual studio GUI.

I hope to be able to do it this was as I will be using more of the confirm boxes for my buttons in my gridview.

blooper0222-Nov-07 21:59

Avoid redrawing flash with postback

22-Nov-07 21:59

Yes Yes Yes Finally....

It should be like this:

<asp:button id="btnUpdate" runat="server" causesvalidation="true" commandname="Update" text="Update" validationgroup="EditValidate" onclientclick="if (!confirm('Update?')) return false">

Solution courtesy of :
http://aspalliance.com/699_Solving_the_Challenges_of_ASPNET_Validation.6

Finally after 2 weeks.....zzzzzzz

Jan Hirak20-Nov-07 23:27

Jan Hirak

20-Nov-07 23:27

I have web site with Macromedia Flash menu. After clicking on each menu item I would like to display different page, but I want to avoid redrawing flash control after each postback. What is the best way to achieve this ? I dont want to use frames.

Prakash_Mishra21-Nov-07 0:44

Prakash_Mishra

21-Nov-07 0:44

hi friend

I am not sure about this but using AJAX may solve this problem so each time you click menu item the page will not refreshed from the server and you can avoid redrawing flash control.

Prakash Mishra(Banglore,India)

Jan Hirak21-Nov-07 1:04

Jan Hirak

21-Nov-07 1:04

Yes I was thinking about this as probably the best solution, but I'm not sure how to implement this. I was hoping somebody points me to some good tutorial as I colud not find any.

Malcolm Smart21-Nov-07 1:26

Malcolm Smart

21-Nov-07 1:26

You can't find a tutorial on Ajax techniques?

17 million of them here...[^]

"More functions should disregard input values and just return 12. It would make life easier." - comment posted on WTF

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