DataGris Paging not working (event not firing)

[Ryan Rueckl]

Hello,

It seems that no matter what I do, I cannot get paging working on my
datagrid. I'll try to explain as best as I can how my program behaves. I
did build the datagrid properties in the designer first, not at runtime,
including the bound columns I use. I have it set to allow paging with 25
pages. I then went into the events, named the PageIndexChanged event
('PageChange'), and double click the event to load it into the code. It
looks as if it is loaded fine - in InitializeComponent there is
this.DataGrid1.PageIndexChanged += new
System.Web.UI.WebControls.DataGridPageChangedEventHandler(this.PageChange);

and there is the corresponding method at the end of the class.

I also have a seperate class 'DataSource' - the constructor creates a new
empty dataset. It has a Refresh method that gets called when the page gets
updated (also when it loads) that adds a table to the dataset by calling a
GetAccounts method which returns a datatable. In this GetAccounts method is
where i build the datatable with columns that match the bound columns of the
datagrid and populate the table with my data.

When the program first starts, its creates an instance of the DataSource
class. When the page load method is called, if it's not a postback it calls
an update function, which calls the DataSource Refresh method and then binds
the datagrid to the dataset built in DataSource instance.

I know it sounds complicated but is based off a Microsoft example. Without
paging works great - all the data shows up. When i turn the paging on, the
first page with 25 rows shows up, but when I click the > Next arrow, the
datagrid disappears. I put a stop/breakpoint in the PageChange method to
see if it ever even gets called and it doesn't. I also put a different stop
point in the page load function and notice the all my data previously in the
grid source is gone, even though I have EnableViewState set to true.

Anybody have any ideas? I really thought datagrids would be a little more
straightforward than this. It is quite frustrating.

Thanks,
Ryan

 

[Elton Wang]

Hi Ryan,

Basically, a web application is stateless. Once rendering to client-side, it
's data gone, unless you explicitly keep some data, e.g. in SessionState,
ApplicationState, ViewSate, or Cookies. In datagrid pagination,
PageIndexChanged event, following code should be done:



datagrid.CurrentPageIndex = e.NewPageIndex;
datagrid.DataSource = data_source_object;
// data_source_object is either from re-query from DB or from Session (if it
's saved there before)
datagrid.DataBind();


HTH

 

[Ryan Rueckl]

Thank you very much for your reply. Here's where the problem comes in. The
PageIndexChanged event doesn't ever fire. I know because I have a label
that I change in that event, and when I press the link on the web page to go
to the next datagrid page, the label doesn't change. If I can just get the
event to fire correctly, I have ViewState enabled so that shouldn't be a
problem. I just need to know why it isn't firing.

 

[Elton Wang]

Could you show both html and c# code?

Thank you very much for your reply. Here's where the problem comes in. The
PageIndexChanged event doesn't ever fire. I know because I have a label
that I change in that event, and when I press the link on the web page to go
to the next datagrid page, the label doesn't change. If I can just get the
event to fire correctly, I have ViewState enabled so that shouldn't be a
problem. I just need to know why it isn't firing.

 

[Ryan Rueckl]

Elton,

I came across something else weird happening. In the code I sent you I
created the datagrid bound columns at runtime in the code. But when I tried
taking that code out and creating them in the designer, the
DataGrid.DataBind() call caused the program to crash. I didn't change any
other code, only the way the bound columns are created. I get this error:
Server Error in '/GetAccountTotals' Application.
--------------------------------------------------------------------------------

Index (zero based) must be greater than or equal to zero and less than the
size of the argument list.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.FormatException: Index (zero based) must be
greater than or equal to zero and less than the size of the argument list.

Source Error:

Line 135:// DataGrid1.DataSource = dv;
Line 136:
Line 137: DataGrid1.DataBind();
Line 138:x=x;
Line 139:// Page.EnableViewState = true;

 

[Ryan Rueckl]

Elton,

OK, I got rid of the FormatException. I was trying to format the datagrid
columns using the designer, but if your data values don't match the column
format, it throws an exception, so I took the formatting off and the grid
and values show up fine. So at this point I used the designer to create my
bound columns, not in the code. In my code I create the data source and
bind it to the datagrid. Turned paging on and it STILL does not fire the
PageIndexChanged event. I don't know what else I need to do to get that
event to work.

Any ideas? If necessary, I can send you my revised code, although it didn't
really change much except I don't create the datagrid columns in the code
and they are listed in the html.

Ryan


--------------------------------------------------------------------------------

From: Elton Wang [mailto:[email protected]]
Sent: Thursday, June 23, 2005 2:36 PM
To: Ryan Rueckl
Subject: Re: DataGris Paging not working (event not firing)

Hi Ryan,

Currently, I'm not sure what causes FormatException. Since you mentioned you
changed datagrid, there may be something wrong in your datagrid html code.
However, one thing is for sure, paging problem is from runtime created bound
columns. Many people reported problems of dynamic datagrid columns. That
causes malfunctions of sorting, paging. So if possible, use static columns.

Elton

----- Original Message -----

From: Ryan Rueckl

To: (e-mail address removed)

Sent: Thursday, June 23, 2005 1:14 PM

Subject: Re: DataGris Paging not working (event not firing)

 

[Elton Wang]

Hi Ryan,

You should also set datagrid AllowPaging="True" and PageSize (if it's not
10).

Elton

Elton,

OK, I got rid of the FormatException. I was trying to format the datagrid
columns using the designer, but if your data values don't match the column
format, it throws an exception, so I took the formatting off and the grid
and values show up fine. So at this point I used the designer to create my
bound columns, not in the code. In my code I create the data source and
bind it to the datagrid. Turned paging on and it STILL does not fire the
PageIndexChanged event. I don't know what else I need to do to get that
event to work.

Any ideas? If necessary, I can send you my revised code, although it didn't
really change much except I don't create the datagrid columns in the code
and they are listed in the html.

Ryan


-------------------------------------------------------------------------- ------

From: Elton Wang [mailto:[email protected]]
Sent: Thursday, June 23, 2005 2:36 PM
To: Ryan Rueckl
Subject: Re: DataGris Paging not working (event not firing)

Hi Ryan,

Currently, I'm not sure what causes FormatException. Since you mentioned you
changed datagrid, there may be something wrong in your datagrid html code.
However, one thing is for sure, paging problem is from runtime created bound
columns. Many people reported problems of dynamic datagrid columns. That
causes malfunctions of sorting, paging. So if possible, use static columns.

Elton

----- Original Message -----

From: Ryan Rueckl

To: (e-mail address removed)

Sent: Thursday, June 23, 2005 1:14 PM

Subject: Re: DataGris Paging not working (event not firing)

Elton,

I came across something else weird happening. In the code I sent you I
created the datagrid bound columns at runtime in the code. But when I
tried taking that code out and creating them in the designer, the
DataGrid.DataBind() call caused the program to crash. I didn't change any
other code, only the way the bound columns are created. I get this error:
Server Error in '/GetAccountTotals' Application.
-------------------------------------------------------------------------- ------

Index (zero based) must be greater than or equal to zero and less than the
size of the argument list.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.FormatException: Index (zero based) must be
greater than or equal to zero and less than the size of the argument list.

Source Error:

Line 135:// DataGrid1.DataSource = dv;
Line 136:
Line 137: DataGrid1.DataBind();
Line 138:x=x;
Line 139:// Page.EnableViewState = true;

 

[Ryan Rueckl]

Yes, paging is allowed and pagesize is 25. Those were set before I even
posted here. This is getting very frustrating. Ok, I'm going to start from
scratch on a new project. I'll list the steps here to make sure I'm not
missing something.

- Start New Web Application

- drag datagrid onto webform

- set AutoGenerateColumns to false

- set EnableViewState to true

- set AllowPaging to true, with PageSize of 25

- using the datagrid property builder, create all of my bound columns needed
(including 1 hidden column)

- In Page_Load, if(!Page.IsPostBack) call my Update() method which creates
the dataset, adds the data to it, sets the datagrid's datasource = dataset,
then calls databind()

- in the designer, highlight datagrid -> in datagrid properties, choose
events -> double click on the PageIndexChanged event

- make sure the event handler in added in the InitializeComponent() method

- in the DataGrid1_PageIndexChanged event handler ->
DataGrid1.CurrentPageIndex = e.NewPageIndex; -> then call my Update() method
again which recreates the dataset, adds data, sets the datagrid datasource =
dataset, and calls DataBind()

After I do all this, theoretically when I click on Build and Run, the web
page will come up, the datagrid will have 25 lines of data with the < >
links at the bottom, when I click the > forward link, the next 25 lines of
data should appear in the datagrid. As I have said, at this point in my
other attempts the datagrid just disappears.

If I have something wrong or am missing anything here, please let me know.
Also, if you can let me know if this is right, I'll wait until then and then
give it another try, and report back if it works.

Thanks,

Ryan

Hi Ryan,

You should also set datagrid AllowPaging="True" and PageSize (if it's not
10).

Elton

Elton,

OK, I got rid of the FormatException. I was trying to format the
datagrid
columns using the designer, but if your data values don't match the
column
format, it throws an exception, so I took the formatting off and the grid
and values show up fine. So at this point I used the designer to create my
bound columns, not in the code. In my code I create the data source and
bind it to the datagrid. Turned paging on and it STILL does not fire the
PageIndexChanged event. I don't know what else I need to do to get that
event to work.

Any ideas? If necessary, I can send you my revised code, although it didn't
really change much except I don't create the datagrid columns in the code
and they are listed in the html.

Ryan


-------------------------------------------------------------------------- ------

From: Elton Wang [mailto:[email protected]]
Sent: Thursday, June 23, 2005 2:36 PM
To: Ryan Rueckl
Subject: Re: DataGris Paging not working (event not firing)

Hi Ryan,

Currently, I'm not sure what causes FormatException. Since you mentioned you
changed datagrid, there may be something wrong in your datagrid html
code.
However, one thing is for sure, paging problem is from runtime created bound
columns. Many people reported problems of dynamic datagrid columns. That
causes malfunctions of sorting, paging. So if possible, use static columns.

Elton

----- Original Message -----

From: Ryan Rueckl

To: (e-mail address removed)

Sent: Thursday, June 23, 2005 1:14 PM

Subject: Re: DataGris Paging not working (event not firing)

Elton,

I came across something else weird happening. In the code I sent you I
created the datagrid bound columns at runtime in the code. But when I
tried taking that code out and creating them in the designer, the
DataGrid.DataBind() call caused the program to crash. I didn't change any
other code, only the way the bound columns are created. I get this error:
Server Error in '/GetAccountTotals' Application.
-------------------------------------------------------------------------- ------

Index (zero based) must be greater than or equal to zero and less than the
size of the argument list.
Description: An unhandled exception occurred during the execution of
the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.FormatException: Index (zero based) must be
greater than or equal to zero and less than the size of the argument list.

Source Error:

Line 135:// DataGrid1.DataSource = dv;
Line 136:
Line 137: DataGrid1.DataBind();
Line 138:x=x;
Line 139:// Page.EnableViewState = true;





Could you show both html and c# code?


Thank you very much for your reply. Here's where the problem comes in.
The
PageIndexChanged event doesn't ever fire. I know because I have a label
that I change in that event, and when I press the link on the web
page
to
go
to the next datagrid page, the label doesn't change. If I can just get
the
event to fire correctly, I have ViewState enabled so that shouldn't
be a
problem. I just need to know why it isn't firing.

Hi Ryan,

Basically, a web application is stateless. Once rendering to
client-side,
it
's data gone, unless you explicitly keep some data, e.g. in
SessionState,
ApplicationState, ViewSate, or Cookies. In datagrid pagination,
PageIndexChanged event, following code should be done:



datagrid.CurrentPageIndex = e.NewPageIndex;
datagrid.DataSource = data_source_object;
// data_source_object is either from re-query from DB or from Session
(if
it
's saved there before)
datagrid.DataBind();


HTH





Hello,

It seems that no matter what I do, I cannot get paging working on my
datagrid. I'll try to explain as best as I can how my program
behaves.
I
did build the datagrid properties in the designer first, not at
runtime,
including the bound columns I use. I have it set to allow paging
with
25
pages. I then went into the events, named the PageIndexChanged event
('PageChange'), and double click the event to load it into the code.
It
looks as if it is loaded fine - in InitializeComponent there is
this.DataGrid1.PageIndexChanged += new


System.Web.UI.WebControls.DataGridPageChangedEventHandler(this.PageChange);

and there is the corresponding method at the end of the class.

I also have a seperate class 'DataSource' - the constructor
creates a
new
empty dataset. It has a Refresh method that gets called when the
page
gets
updated (also when it loads) that adds a table to the dataset by
calling
a
GetAccounts method which returns a datatable. In this GetAccounts
method
is
where i build the datatable with columns that match the bound columns
of
the
datagrid and populate the table with my data.

When the program first starts, its creates an instance of the
DataSource
class. When the page load method is called, if it's not a
postback
it
calls
an update function, which calls the DataSource Refresh method and
then
binds
the datagrid to the dataset built in DataSource instance.

I know it sounds complicated but is based off a Microsoft example.
Without
paging works great - all the data shows up. When i turn the
paging
on,
the
first page with 25 rows shows up, but when I click the > Next arrow,
the
datagrid disappears. I put a stop/breakpoint in the PageChange
method
to
see if it ever even gets called and it doesn't. I also put a
different
stop
point in the page load function and notice the all my data previously
in
the
grid source is gone, even though I have EnableViewState set to true.

Anybody have any ideas? I really thought datagrids would be a little
more
straightforward than this. It is quite frustrating.

Thanks,
Ryan

 

[Ryan Rueckl]

I just moved my code to a different machine and the paging worked!! I don't
know why it wouldn't work on the other machine. At least I have confirmed
that my code was right all along. Any ideas as to why it wouldn't work on
the original machine?



Anybody?



Ryan

Yes, paging is allowed and pagesize is 25. Those were set before I even
posted here. This is getting very frustrating. Ok, I'm going to start from
scratch on a new project. I'll list the steps here to make sure I'm not
missing something.

- Start New Web Application

- drag datagrid onto webform

- set AutoGenerateColumns to false

- set EnableViewState to true

- set AllowPaging to true, with PageSize of 25

- using the datagrid property builder, create all of my bound columns
needed (including 1 hidden column)

- In Page_Load, if(!Page.IsPostBack) call my Update() method which creates
the dataset, adds the data to it, sets the datagrid's datasource =
dataset, then calls databind()

- in the designer, highlight datagrid -> in datagrid properties, choose
events -> double click on the PageIndexChanged event

- make sure the event handler in added in the InitializeComponent() method

- in the DataGrid1_PageIndexChanged event handler ->
DataGrid1.CurrentPageIndex = e.NewPageIndex; -> then call my Update()
method again which recreates the dataset, adds data, sets the datagrid
datasource = dataset, and calls DataBind()

After I do all this, theoretically when I click on Build and Run, the web
page will come up, the datagrid will have 25 lines of data with the < >
links at the bottom, when I click the > forward link, the next 25 lines of
data should appear in the datagrid. As I have said, at this point in my
other attempts the datagrid just disappears.

If I have something wrong or am missing anything here, please let me know.
Also, if you can let me know if this is right, I'll wait until then and
then give it another try, and report back if it works.

Thanks,

Ryan

Hi Ryan,

You should also set datagrid AllowPaging="True" and PageSize (if it's not
10).

Elton

Elton,

OK, I got rid of the FormatException. I was trying to format the
datagrid
columns using the designer, but if your data values don't match the
column
format, it throws an exception, so I took the formatting off and the
grid
and values show up fine. So at this point I used the designer to create my
bound columns, not in the code. In my code I create the data source and
bind it to the datagrid. Turned paging on and it STILL does not fire
the
PageIndexChanged event. I don't know what else I need to do to get that
event to work.

Any ideas? If necessary, I can send you my revised code, although it didn't
really change much except I don't create the datagrid columns in the
code
and they are listed in the html.

Ryan


-------------------------------------------------------------------------- ------

From: Elton Wang [mailto:[email protected]]
Sent: Thursday, June 23, 2005 2:36 PM
To: Ryan Rueckl
Subject: Re: DataGris Paging not working (event not firing)

Hi Ryan,

Currently, I'm not sure what causes FormatException. Since you mentioned you
changed datagrid, there may be something wrong in your datagrid html
code.
However, one thing is for sure, paging problem is from runtime created bound
columns. Many people reported problems of dynamic datagrid columns. That
causes malfunctions of sorting, paging. So if possible, use static columns.

Elton

----- Original Message -----

From: Ryan Rueckl

To: (e-mail address removed)

Sent: Thursday, June 23, 2005 1:14 PM

Subject: Re: DataGris Paging not working (event not firing)

Elton,

I came across something else weird happening. In the code I sent you
I
created the datagrid bound columns at runtime in the code. But when I
tried taking that code out and creating them in the designer, the
DataGrid.DataBind() call caused the program to crash. I didn't change any
other code, only the way the bound columns are created. I get this error:
Server Error in '/GetAccountTotals' Application.

-------------------------------------------------------------------------- ------

Index (zero based) must be greater than or equal to zero and less than the
size of the argument list.
Description: An unhandled exception occurred during the execution of
the
current web request. Please review the stack trace for more
information
about the error and where it originated in the code.

Exception Details: System.FormatException: Index (zero based) must be
greater than or equal to zero and less than the size of the argument list.

Source Error:

Line 135:// DataGrid1.DataSource = dv;
Line 136:
Line 137: DataGrid1.DataBind();
Line 138:x=x;
Line 139:// Page.EnableViewState = true;





Could you show both html and c# code?


Thank you very much for your reply. Here's where the problem comes in.
The
PageIndexChanged event doesn't ever fire. I know because I have a label
that I change in that event, and when I press the link on the web
page
to
go
to the next datagrid page, the label doesn't change. If I can just get
the
event to fire correctly, I have ViewState enabled so that shouldn't
be a
problem. I just need to know why it isn't firing.

Hi Ryan,

Basically, a web application is stateless. Once rendering to
client-side,
it
's data gone, unless you explicitly keep some data, e.g. in
SessionState,
ApplicationState, ViewSate, or Cookies. In datagrid pagination,
PageIndexChanged event, following code should be done:



datagrid.CurrentPageIndex = e.NewPageIndex;
datagrid.DataSource = data_source_object;
// data_source_object is either from re-query from DB or from Session
(if
it
's saved there before)
datagrid.DataBind();


HTH





Hello,

It seems that no matter what I do, I cannot get paging working on my
datagrid. I'll try to explain as best as I can how my program
behaves.
I
did build the datagrid properties in the designer first, not at
runtime,
including the bound columns I use. I have it set to allow paging
with
25
pages. I then went into the events, named the PageIndexChanged event
('PageChange'), and double click the event to load it into the code.
It
looks as if it is loaded fine - in InitializeComponent there is
this.DataGrid1.PageIndexChanged += new


System.Web.UI.WebControls.DataGridPageChangedEventHandler(this.PageChange);

and there is the corresponding method at the end of the class.

I also have a seperate class 'DataSource' - the constructor
creates a
new
empty dataset. It has a Refresh method that gets called when the
page
gets
updated (also when it loads) that adds a table to the dataset by
calling
a
GetAccounts method which returns a datatable. In this
GetAccounts
method
is
where i build the datatable with columns that match the bound columns
of
the
datagrid and populate the table with my data.

When the program first starts, its creates an instance of the
DataSource
class. When the page load method is called, if it's not a
postback
it
calls
an update function, which calls the DataSource Refresh method and
then
binds
the datagrid to the dataset built in DataSource instance.

I know it sounds complicated but is based off a Microsoft
example.
Without
paging works great - all the data shows up. When i turn the
paging
on,
the
first page with 25 rows shows up, but when I click the > Next arrow,
the
datagrid disappears. I put a stop/breakpoint in the PageChange
method
to
see if it ever even gets called and it doesn't. I also put a
different
stop
point in the page load function and notice the all my data previously
in
the
grid source is gone, even though I have EnableViewState set to true.

Anybody have any ideas? I really thought datagrids would be a little
more
straightforward than this. It is quite frustrating.

Thanks,
Ryan