XSD VS.Net

[Leon Shaw]

After configuring a relation data schema (MyDataSet.xsd) in vs.net, what
code do you use to display that data within two dropdownlist controls (
parent/child) in an web application?

 

[Marc Hoeppner]

Hi Leon,

configuring a typed dataset only gets you halfway there (assuming that's
what you are doing with the XSD). What you still need to do by hand is to
write some ADO.NET code to establish the connection with the database and to
actually load stuff in your dataset. For example, you could define a
SqlDataAdapter, specify a SELECT... query and use .Fill with your typed
DataSet as parameter (if you use SQL Server). It may be a little overkill to
define a typed dataset and use a DataAdapter only to fill two dropdownlists.
Take a look at the Data Access Application
Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx
?pull=/library/en-us/dnbda/html/daab-rm.asp), it could be as easy as this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you may want to use a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo

 

[Leon Shaw]

Ok I have call the adatper.fill and databind command, but is'nt some type of
code such as Me.DataSet1.WriteXmlSchema(Me.Request.ApplicationPath
"DataSet1.xsd" I have to type to get the database schema from the .xsd file
(I have two relate tables in my .xsd file "States" and "School". when you
select a state from the first dropdownlist the second dropdownlist suppose
to populate itself with the correct schools from that state. However, the
first list populate with the states, (I have autopostback set to true, and
the onchange event firing) but after the page postback the state
dropdownlist displays System.Data.RelatedView over and over again. Thanks
for the help!

Hi Leon,

configuring a typed dataset only gets you halfway there (assuming that's
what you are doing with the XSD). What you still need to do by hand is to
write some ADO.NET code to establish the connection with the database and to
actually load stuff in your dataset. For example, you could define a
SqlDataAdapter, specify a SELECT... query and use .Fill with your typed
DataSet as parameter (if you use SQL Server). It may be a little overkill to
define a typed dataset and use a DataAdapter only to fill two dropdownlists.
Take a look at the Data Access Application
Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx
?pull=/library/en-us/dnbda/html/daab-rm.asp), it could be as easy as this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you may want to use a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo

After configuring a relation data schema (MyDataSet.xsd) in vs.net, what
code do you use to display that data within two dropdownlist controls (
parent/child) in an web application?

 

[Marc Hoeppner]

Well, basically you can have VS.NET do the grunt work for you. If you
right-click on your project file, select add, then add class, select dataset
and use any name you like (dataset1.xsd) is fine. Now use the server
explorer to drag a few tables in the XSD and use the toolbox to add
references and/or new fields as needed. Now, when you do this and compile
your project, VS.NET will use a tool (XGEN.EXE) to generate a C# file for
you that implements a strongly typed dataset. You can use it like any other
dataset but it is also a strongly typed class with all the parameters that
your tables have. You can also manually change the XSD file or use the GUI
to build your XSD from scratch.

But if all you want to do is to fill two DropDownLists I would recommend to
use the Data Access Application Blocks or simple ADO.NET to get a DataTable
for each table separately and attach these to the dropdownlists.

One other thing: you can help the databind process to find the right columns
to display by the user of DataTextField and DataValueField. For example, if
you have a DataTable with 4 columns (Company, Street, Country, CompanyID)
and you want the ddl to display the Company as text and have the CompanyID
as the value you'd do something like this:

MyDropDownList.DataSource = MyDataTable;
MyDropDownList.DataTextField = "Company";
MyDropDownList.DataValueField = "CompanyID";
MyDropDownList.DataBind();

Hope this helps!!

Best regards,

Marc Höppner
NeoGeo

Ok I have call the adatper.fill and databind command, but is'nt some type of
code such as Me.DataSet1.WriteXmlSchema(Me.Request.ApplicationPath
"DataSet1.xsd" I have to type to get the database schema from the .xsd file
(I have two relate tables in my .xsd file "States" and "School". when you
select a state from the first dropdownlist the second dropdownlist suppose
to populate itself with the correct schools from that state. However, the
first list populate with the states, (I have autopostback set to true, and
the onchange event firing) but after the page postback the state
dropdownlist displays System.Data.RelatedView over and over again. Thanks
for the help!

Hi Leon,

configuring a typed dataset only gets you halfway there (assuming that's
what you are doing with the XSD). What you still need to do by hand is to
write some ADO.NET code to establish the connection with the database

and

to
actually load stuff in your dataset. For example, you could define a
SqlDataAdapter, specify a SELECT... query and use .Fill with your typed
DataSet as parameter (if you use SQL Server). It may be a little

overkill

to
define a typed dataset and use a DataAdapter only to fill two dropdownlists.
Take a look at the Data Access Application

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it could be as easy as this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you may want to

use

a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo

 

[Leon Shaw]

do you have remote desktop. I would like you to see want I'm doing for
yourself. I have did everything you stated, and have reference multiple
books and is yet to solve the problem. I thinking of setting up a parameter
stored procedure to get the state id to binding the right schools for that
state in the dropdownlist. The reason I chose the .xsd relational dataset
route, it easy to define relationships among tables. What do you think?

Well, basically you can have VS.NET do the grunt work for you. If you
right-click on your project file, select add, then add class, select dataset
and use any name you like (dataset1.xsd) is fine. Now use the server
explorer to drag a few tables in the XSD and use the toolbox to add
references and/or new fields as needed. Now, when you do this and compile
your project, VS.NET will use a tool (XGEN.EXE) to generate a C# file for
you that implements a strongly typed dataset. You can use it like any other
dataset but it is also a strongly typed class with all the parameters that
your tables have. You can also manually change the XSD file or use the GUI
to build your XSD from scratch.

But if all you want to do is to fill two DropDownLists I would recommend to
use the Data Access Application Blocks or simple ADO.NET to get a DataTable
for each table separately and attach these to the dropdownlists.

One other thing: you can help the databind process to find the right columns
to display by the user of DataTextField and DataValueField. For example, if
you have a DataTable with 4 columns (Company, Street, Country, CompanyID)
and you want the ddl to display the Company as text and have the CompanyID
as the value you'd do something like this:

MyDropDownList.DataSource = MyDataTable;
MyDropDownList.DataTextField = "Company";
MyDropDownList.DataValueField = "CompanyID";
MyDropDownList.DataBind();

Hope this helps!!

Best regards,

Marc Höppner
NeoGeo

Ok I have call the adatper.fill and databind command, but is'nt some

type

of
code such as Me.DataSet1.WriteXmlSchema(Me.Request.ApplicationPath
"DataSet1.xsd" I have to type to get the database schema from the .xsd file
(I have two relate tables in my .xsd file "States" and "School". when you
select a state from the first dropdownlist the second dropdownlist suppose
to populate itself with the correct schools from that state. However, the
first list populate with the states, (I have autopostback set to true, and
the onchange event firing) but after the page postback the state
dropdownlist displays System.Data.RelatedView over and over again. Thanks
for the help!

and overkill

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it could be as easy as this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you may want to

use

a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo


After configuring a relation data schema (MyDataSet.xsd) in vs.net, what
code do you use to display that data within two dropdownlist

controls

(

 

[Marc Hoeppner]

I am not sure I get what you want to do. Could you elaborate a little?

webform2.aspx is not good going practice at all as I load all customers and
all orders into the typed dataset. I think webform1.aspx is a much, much
better implementation (faster, easier to read, easier to change, faster...).

how do do that same code but reference the name of the relationship such as
(CustomersOrders) in the DataSet1.xsd file to populate the dropdownlist.

With regards to your application, I still think there is an easier way

to

do
that. I am sure you know that by now, but just to be safe: You need be aware
that typed datasets don't write the code for you to access and retrieve
data. You still need to do all the loading/saving etc. yourself in code.
Also, the databinding process for web controls does not automatically take
care of connected tables inside a dataset (typed or not), you also have to
do this yourself.

The straight-forward approach to solving your problem (using the Northwind
database) is attached to this post on page webform1.aspx. You need to edit
the connection string and the sample is done using SQL Server or MSDE. The
typed dataset version is on page webform2.aspx.

And yes, I have remote desktop, so we can set up a time if you want to and
I'll give it a quick look.


file
for parameters
that the
GUI hand

define

a

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx easy

as

this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you may

want

to
use
a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo


After configuring a relation data schema (MyDataSet.xsd) in vs.net,
what
code do you use to display that data within two dropdownlist
controls
(
parent/child) in an web application?

 

[Leon Shaw]

So I should set up a store procedure in my MS SQL 2000 database for cities
(@StateID) and get the StateDropDownList.DataValueField and pass that value
(@StateID) to display the correct Schools in the SchoolDropDownlist?
Correct!

I am not sure I get what you want to do. Could you elaborate a little?

webform2.aspx is not good going practice at all as I load all customers and
all orders into the typed dataset. I think webform1.aspx is a much, much
better implementation (faster, easier to read, easier to change, faster...).

how do do that same code but reference the name of the relationship such as
(CustomersOrders) in the DataSet1.xsd file to populate the dropdownlist.

to

have

to for
that the
.xsd define

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it could be as

easy

as
this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you may want
to
use
a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo


After configuring a relation data schema (MyDataSet.xsd) in
vs.net,
what
code do you use to display that data within two dropdownlist
controls
(
parent/child) in an web application?

 

[Marc Hoeppner]

Yes, you can do that!

So I should set up a store procedure in my MS SQL 2000 database for cities
(@StateID) and get the StateDropDownList.DataValueField and pass that value
(@StateID) to display the correct Schools in the SchoolDropDownlist?
Correct!

I am not sure I get what you want to do. Could you elaborate a little?

webform2.aspx is not good going practice at all as I load all customers and
all orders into the typed dataset. I think webform1.aspx is a much, much
better implementation (faster, easier to read, easier to change, faster...).

such
as way
to automatically
take have to
edit MSDE.
The to
and If
you like
any use
the is'nt
some

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it could be as easy
as
this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you may
want
to
use
a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo


After configuring a relation data schema (MyDataSet.xsd) in
vs.net,
what
code do you use to display that data within two dropdownlist
controls
(
parent/child) in an web application?

 

[Leon Shaw]

is that a better way, and more efficient way of doing it? However, Thanks
for all the help!

Yes, you can do that!

So I should set up a store procedure in my MS SQL 2000 database for cities
(@StateID) and get the StateDropDownList.DataValueField and pass that value
(@StateID) to display the correct Schools in the SchoolDropDownlist?
Correct!


customers
and

need

be

want

to doing
for schools
for to
add

get

a from
the

set

to

do

by

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it could be as
easy
as
this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you may
want
to
use
a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo


After configuring a relation data schema (MyDataSet.xsd) in
vs.net,
what
code do you use to display that data within two dropdownlist
controls
(
parent/child) in an web application?

 

[Leon Shaw]

I GOT IT TO WORK. THANKS SO MUCH, but so What you are saying is that I don't
even have to use a dataset at all. All I really need to do is use
sqlcommands to pull data into my form for easy selection Then use a dataset
to pull all the information from every form field and update the database?
Correct

The method used in webform1.aspx should be a lot better than using typed
datasets in this case. Depending on your scenario you could some caching or
even load all the orders (in this case) in a dataset if all customers get
selected pretty frequently.

If you still shoot for the typed dataset, you can start with the
webform2.aspx sample and go from there. You can change the sample to use
SPROCs instead of inline SQL, but you still will have to do the filtering of
the dataset either in T-SQL or by use of the Select or Filter functions in
DataSet/DataTable manually.

is that a better way, and more efficient way of doing it? However, Thanks
for all the help!
much,
much

yourself

in up toolbox
to

generate

a

file

or to
get DataValueField.
For have
the autopostback
set to
do with
the ..Fill
with

be

a

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it could

be

as
easy
as
this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet( MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead, so you
may
want
to
use
a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo


After configuring a relation data schema (MyDataSet.xsd)
in
vs.net,
what
code do you use to display that data within two
dropdownlist
controls
(
parent/child) in an web application?

 

[Marc Hoeppner]

Great, congrats!!

A dataset is very powerfull on the one hand, but on the other has a lot of
overhead. So you need to use it appropriately. Yes, you don't need a dataset
to fill a dropdownlist, but you also have to count other factors such as
ease of use and amount of code to type. So, I'd use something similar to the
webform1.aspx approach and make sure that the page caching is set to a long
time period if your data does not changes very often. This way you have the
ease of use as in the first sample, but the database code only gets called a
few times a time for example. So, this was selecting data.
Inserting/updating data can be done by a dataset as well, but if you only
update a few items in a form you can as well use an SPROC and send it the
values from your form directly without a dataset. If you have a larger
application and use data over and over again on different pages, it may be a
good idea to build a couple of typed datasets where appropriate and use them
both for selecting and for inserting/updating.

I GOT IT TO WORK. THANKS SO MUCH, but so What you are saying is that I don't
even have to use a dataset at all. All I really need to do is use
sqlcommands to pull data into my form for easy selection Then use a dataset
to pull all the information from every form field and update the database?
Correct

The method used in webform1.aspx should be a lot better than using typed
datasets in this case. Depending on your scenario you could some caching or
even load all the orders (in this case) in a dataset if all customers get
selected pretty frequently.

If you still shoot for the typed dataset, you can start with the
webform2.aspx sample and go from there. You can change the sample to use
SPROCs instead of inline SQL, but you still will have to do the

filtering

of
the dataset either in T-SQL or by use of the Select or Filter functions in
DataSet/DataTable manually.


yourself you
also You
need

Server

or setting
up do
you for
you. use
the generate

use

it file find
the

need

to be

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it

could
be

as
easy
as
this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet(
MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some overhead,

so
you

may
want
to
use
a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo


After configuring a relation data schema (MyDataSet.xsd)
in
vs.net,
what
code do you use to display that data within two
dropdownlist
controls
(
parent/child) in an web application?

 

[Leon Shaw]

Thanks So Much! I will surely apply and share the knowledge.

Great, congrats!!

A dataset is very powerfull on the one hand, but on the other has a lot of
overhead. So you need to use it appropriately. Yes, you don't need a dataset
to fill a dropdownlist, but you also have to count other factors such as
ease of use and amount of code to type. So, I'd use something similar to the
webform1.aspx approach and make sure that the page caching is set to a long
time period if your data does not changes very often. This way you have the
ease of use as in the first sample, but the database code only gets called a
few times a time for example. So, this was selecting data.
Inserting/updating data can be done by a dataset as well, but if you only
update a few items in a form you can as well use an SPROC and send it the
values from your form directly without a dataset. If you have a larger
application and use data over and over again on different pages, it may be a
good idea to build a couple of typed datasets where appropriate and use them
both for selecting and for inserting/updating.

I GOT IT TO WORK. THANKS SO MUCH, but so What you are saying is that I don't
even have to use a dataset at all. All I really need to do is use
sqlcommands to pull data into my form for easy selection Then use a dataset
to pull all the information from every form field and update the database?
Correct
caching
or filtering

functions

in (using
the Server

What

do use ADO.NET
to and
have command,
but postback
the need connection
with may
be

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it could
be
as
easy
as
this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet(
MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some

overhead,

so

 

[Marc Hoeppner]

Excellent, glad to be of help!

Thanks So Much! I will surely apply and share the knowledge.

Great, congrats!!

A dataset is very powerfull on the one hand, but on the other has a lot of
overhead. So you need to use it appropriately. Yes, you don't need a dataset
to fill a dropdownlist, but you also have to count other factors such as
ease of use and amount of code to type. So, I'd use something similar to the
webform1.aspx approach and make sure that the page caching is set to a long
time period if your data does not changes very often. This way you have the
ease of use as in the first sample, but the database code only gets

called

a
few times a time for example. So, this was selecting data.
Inserting/updating data can be done by a dataset as well, but if you only
update a few items in a form you can as well use an SPROC and send it the
values from your form directly without a dataset. If you have a larger
application and use data over and over again on different pages, it may

be

a
good idea to build a couple of typed datasets where appropriate and use them
both for selecting and for inserting/updating.

customers
get functions database
for safe:
You access
and not),
you webform1.aspx.
You if
you want
I'm What work
for Now
use

you

do can
use all
the

DropDownLists

I to
find example,
you

only

to

Blocks(http://msdn.microsoft.com/netframework/downloads/samples/default.aspx

?pull=/library/en-us/dnbda/html/daab-rm.asp), it could
be
as
easy
as
this
(C#):

DataSet MyDs = SqlHelper.ExecuteDataSet(
MyConnectionString,
CommandType.Text, "select name, value from mytable" );

MyDropDownList.DataSource = MyDs.Tables[0];
MyDropDownList.DataTextField = "name";
MyDropDownList.DataValueField = "value";
MyDropDownList.DataBind();

Note that using a dataset always has some

overhead,

so
you
may
want
to
use
a
SqlDataReader for performance.

Best regards,

Marc Hoeppner
NeoGeo


After configuring a relation data schema
(MyDataSet.xsd)
in
vs.net,
what
code do you use to display that data within two
dropdownlist
controls
(
parent/child) in an web application?