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Navigating a dataset

P: n/a
I am having no problems connecting to a DB, creating a DataAdapter,
and creating a dataset...and connecting to the data. Using the
builtin data objects to do all this.

My only problem now is navigating through the data. I can get the
data into a datagrid without any problems, but I want the data to show
up in textboxes and use some sort of move next, move previous, move
last, etc (like in VB6) command to navigate the data (using
buttonX_click). I have been using the learnvisualstudio.net videos
and they are great but anyone have a link or tutorial to get me going
on this specific task?

(Learning to crawl again)

Roy Lawson
ro*@xeon.tv
Nov 20 '05 #1
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5 Replies


P: n/a
Roy,

you might try "ADO.NET for the ADO Programmer"
http://msdn.microsoft.com/library/de...us/dndotnet/ht
ml/adonetprogmsdn.asp

HTHs

Daniel
"Roy Lawson" <ro*@xeon.tv> schrieb im Newsbeitrag
news:c4**************************@posting.google.c om...
I am having no problems connecting to a DB, creating a DataAdapter,
and creating a dataset...and connecting to the data. Using the
builtin data objects to do all this.

My only problem now is navigating through the data. I can get the
data into a datagrid without any problems, but I want the data to show
up in textboxes and use some sort of move next, move previous, move
last, etc (like in VB6) command to navigate the data (using
buttonX_click). I have been using the learnvisualstudio.net videos
and they are great but anyone have a link or tutorial to get me going
on this specific task?

(Learning to crawl again)

Roy Lawson
ro*@xeon.tv


Nov 20 '05 #2

P: n/a
Roy,

maybe it helps you if you imagine the following:

The DataSet object contains a collection of zero or more DataTable objects, each of which is an in-memory representation of a single table. The structure of a particular DataTable is defined by the DataColumns collection, which enumerates the columns in a particular table, and the Constraint collection, which enumerates any constraints on the table. Together, these two collections make up the table schema. A DataTable also contains a DataRows collection, which contains the actual data in the DataSet.

The DataSet contains a DataRelations collection. A DataRelation object allows you to create associations between rows in one table and rows in another table. The DataRelations collection enumerates a set of DataRelation objects that define the relationships between tables in the DataSet. For example, consider a DataSet that contains two related tables: an Employees table and a Projects table. In the Employees table, each employee is represented only once and is identified by a unique EmployeeID field. In the Projects table, an employee in charge of a project is identified by the EmployeeID field, but can appear more than once if that employee is in charge of multiple projects. This is an example of a one-to-many relationship; you would use a DataRelation object to define this relationship.

Excerpt from the book "MCAD/MCSD Training Kit-Developing Windows-Based Applications with Microsoft Visual Basic .NET and Microsoft Visual C# ..NET" which I can truly recommend.



If you for example have a table "myTable" in a DataSet "myDataSet" and you want to bind the field "ID" of the first row of the table to a TextBox named TextBox1 do the following:



TextBox1.Text = myDataSet.Tables("myTable").Rows(0).Item("ID").ToS tring



I hope this gives you the general idea. Always visualize the collections in the ADO.NET model.



Best regards

Daniel Walzenbach

"Roy Lawson" <ro*@xeon.tv> schrieb im Newsbeitrag news:c4**************************@posting.google.c om...
I am having no problems connecting to a DB, creating a DataAdapter,
and creating a dataset...and connecting to the data. Using the
builtin data objects to do all this.

My only problem now is navigating through the data. I can get the
data into a datagrid without any problems, but I want the data to show
up in textboxes and use some sort of move next, move previous, move
last, etc (like in VB6) command to navigate the data (using
buttonX_click). I have been using the learnvisualstudio.net videos
and they are great but anyone have a link or tutorial to get me going
on this specific task?

(Learning to crawl again)

Roy Lawson
ro*@xeon.tv

Nov 20 '05 #3

P: n/a
For what I am doing, there are no constraints on the table
(single table only) so there is only 1 DataTable object in
my DataSet. I set it up this way (1 table w/o relations)
just so I could get it going (crawl before walking).

But, your explanation was very helpful and I think with
that I can figure out programaticly how to proceed. I
suspect I need to focus on the DataColumns collection when
it comes to navigating the DataTable within my DataSet.

My code is on my laptop ... I will submit an update to
this post after I figure it out so that others can learn
to walk with me :-)

Thanks!

-Roy

-----Original Message-----
Roy,

maybe it helps you if you imagine the following:

The DataSet object contains a collection of zero or more DataTable objects, each of which is an in-memory
representation of a single table. The structure of a
particular DataTable is defined by the DataColumns
collection, which enumerates the columns in a particular
table, and the Constraint collection, which enumerates any
constraints on the table. Together, these two collections
make up the table schema. A DataTable also contains a
DataRows collection, which contains the actual data in the
DataSet.
The DataSet contains a DataRelations collection. A DataRelation object allows you to create associations
between rows in one table and rows in another table. The
DataRelations collection enumerates a set of DataRelation
objects that define the relationships between tables in
the DataSet. For example, consider a DataSet that contains
two related tables: an Employees table and a Projects
table. In the Employees table, each employee is
represented only once and is identified by a unique
EmployeeID field. In the Projects table, an employee in
charge of a project is identified by the EmployeeID field,
but can appear more than once if that employee is in
charge of multiple projects. This is an example of a one-
to-many relationship; you would use a DataRelation object
to define this relationship.
Excerpt from the book "MCAD/MCSD Training Kit-Developing Windows-Based Applications with Microsoft Visual
Basic .NET and Microsoft Visual C# ..NET" which I can
truly recommend.
If you for example have a table "myTable" in a DataSet "myDataSet" and you want to bind the field "ID" of
the first row of the table to a TextBox named TextBox1 do
the following:
TextBox1.Text = myDataSet.Tables("myTable").Rows(0).Item ("ID").ToString
I hope this gives you the general idea. Always visualize the collections in the ADO.NET model.
Best regards

Daniel Walzenbach

"Roy Lawson" <ro*@xeon.tv> schrieb im Newsbeitrag

news:c4**************************@posting.google.c om...
I am having no problems connecting to a DB, creating a DataAdapter, and creating a dataset...and connecting to the data. Using the builtin data objects to do all this.

My only problem now is navigating through the data. I can get the data into a datagrid without any problems, but I want the data to show up in textboxes and use some sort of move next, move previous, move last, etc (like in VB6) command to navigate the data (using buttonX_click). I have been using the learnvisualstudio.net videos and they are great but anyone have a link or tutorial to get me going on this specific task?

(Learning to crawl again)

Roy Lawson
ro*@xeon.tv

Nov 20 '05 #4

P: n/a
Roy,



what you have to do is to focus on the DataRow collection, as a (single) DataColumn represents the Type of Data which is stored in your Table. I'm sure you won't be surprised when I tell you that a DataRow itself consists of a collection of DataItems which represent the actual values in a table.



Imagine the following:



ID | Name | Comment

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

1 | Smith | Nice guy!

2 | Wilson | Not so nice.

3 | Lawson | Learns ADO.NET.

4 | Miller | Somebody else.



Here is the code to create this table by your own and print it to the console. To execute the code create a new Console Project, delete all the code in it and copy all the code below into it.



' BEGIN OF CODE ************************************************** ***



Public Class ADODotNETExample



Public Shared Sub main()



' Create a Table

Dim myTable As New System.Data.DataTable

' Create a Column

Dim myColumn As System.Data.DataColumn



' set values for a column

myColumn = New System.Data.DataColumn

myColumn.ColumnName = "ID"

myColumn.DataType = System.Type.GetType("System.Int32")

' add Column to Table

myTable.Columns.Add(myColumn)



myColumn = New System.Data.DataColumn

myColumn.ColumnName = "Name"

myColumn.DataType = System.Type.GetType("System.String")

' add Column to Table

myTable.Columns.Add(myColumn)



myColumn = New System.Data.DataColumn

myColumn.ColumnName = "Description"

myColumn.DataType = System.Type.GetType("System.String")

' add Column to Table

myTable.Columns.Add(myColumn)



' Now you have a empty Table (or to be more exactly

' the definition of a table without any rows)



' Create a DataRow. Remember that you don't instanciate

' a DataRow Object (by using the new() operator)

Dim myDataRow As System.Data.DataRow



' get a DataRow from the Table(description) you just created

myDataRow = myTable.NewRow

' and fill it with Life

myDataRow.Item(0) = 1

myDataRow.Item(1) = "Smith"

myDataRow.Item(2) = "Nice guy!"

' now add the DataRow to the DataTable

myTable.Rows.Add(myDataRow)



' and again for the next row

' you can also address the items by name as the

' item property is overloaded

' get a DataRow from the Table(description) you just created

myDataRow = myTable.NewRow

myDataRow.Item("ID") = 2

myDataRow.Item("Name") = "Wilson"

myDataRow.Item("Description") = "Not so nice."

' now add the DataRow to the DataTable

myTable.Rows.Add(myDataRow)



' and again and again...

' get a DataRow from the Table(description) you just created

myDataRow = myTable.NewRow

myDataRow.Item("ID") = 3

myDataRow.Item("Name") = "Lawson"

myDataRow.Item("Description") = "Learns ADO.NET."

' now add the DataRow to the DataTable

myTable.Rows.Add(myDataRow)



' get a DataRow from the Table(description) you just created

myDataRow = myTable.NewRow

myDataRow.Item("ID") = 4

myDataRow.Item("Name") = "Miller"

myDataRow.Item("Description") = "Somebody else."

' now add the DataRow to the DataTable

myTable.Rows.Add(myDataRow)





Console.WriteLine("Content of myTable")

Console.WriteLine()

Console.WriteLine()



' write content of myTable to console



' first goes the Header

For j As System.Int32 = 0 To myTable.Columns.Count - 1

Console.Write(myTable.Columns(j).ColumnName & ControlChars.Tab)

Next



' new line

Console.WriteLine()



' draw horizontal line

For j As System.Int32 = 0 To 50

Console.Write("-")

Next



Console.WriteLine()



' now print the content of the table

For i As System.Int32 = 0 To myTable.Rows.Count - 1

For j As System.Int32 = 0 To myTable.Columns.Count - 1

Console.Write(myTable.Rows(i).Item(j).ToString & ControlChars.Tab)

Next

Console.WriteLine(ControlChars.Tab & " -> Row : " & i.ToString)

Next



' wait for user to press return

Console.ReadLine()



End Sub



End Class



' END OF CODE ************************************************** *****



Hope this gives you the general idea.

Greetings from Germany.



Daniel Walzenbach

"Roy Lawson" <ro*@xeon.tv> schrieb im Newsbeitrag news:06****************************@phx.gbl...
For what I am doing, there are no constraints on the table
(single table only) so there is only 1 DataTable object in
my DataSet. I set it up this way (1 table w/o relations)
just so I could get it going (crawl before walking).

But, your explanation was very helpful and I think with
that I can figure out programaticly how to proceed. I
suspect I need to focus on the DataColumns collection when
it comes to navigating the DataTable within my DataSet.

My code is on my laptop ... I will submit an update to
this post after I figure it out so that others can learn
to walk with me :-)

Thanks!

-Roy

-----Original Message-----
Roy,

maybe it helps you if you imagine the following:

The DataSet object contains a collection of zero or more

DataTable objects, each of which is an in-memory
representation of a single table. The structure of a
particular DataTable is defined by the DataColumns
collection, which enumerates the columns in a particular
table, and the Constraint collection, which enumerates any
constraints on the table. Together, these two collections
make up the table schema. A DataTable also contains a
DataRows collection, which contains the actual data in the
DataSet.

The DataSet contains a DataRelations collection. A

DataRelation object allows you to create associations
between rows in one table and rows in another table. The
DataRelations collection enumerates a set of DataRelation
objects that define the relationships between tables in
the DataSet. For example, consider a DataSet that contains
two related tables: an Employees table and a Projects
table. In the Employees table, each employee is
represented only once and is identified by a unique
EmployeeID field. In the Projects table, an employee in
charge of a project is identified by the EmployeeID field,
but can appear more than once if that employee is in
charge of multiple projects. This is an example of a one-
to-many relationship; you would use a DataRelation object
to define this relationship.

Excerpt from the book "MCAD/MCSD Training Kit-Developing

Windows-Based Applications with Microsoft Visual
Basic .NET and Microsoft Visual C# ..NET" which I can
truly recommend.



If you for example have a table "myTable" in a

DataSet "myDataSet" and you want to bind the field "ID" of
the first row of the table to a TextBox named TextBox1 do
the following:



TextBox1.Text = myDataSet.Tables("myTable").Rows(0).Item

("ID").ToString



I hope this gives you the general idea. Always visualize

the collections in the ADO.NET model.



Best regards

Daniel Walzenbach

"Roy Lawson" <ro*@xeon.tv> schrieb im Newsbeitrag

news:c4**************************@posting.google.c om...
I am having no problems connecting to a DB, creating a DataAdapter, and creating a dataset...and connecting to the data. Using the builtin data objects to do all this.

My only problem now is navigating through the data. I can get the data into a datagrid without any problems, but I want the data to show up in textboxes and use some sort of move next, move previous, move last, etc (like in VB6) command to navigate the data (using buttonX_click). I have been using the learnvisualstudio.net videos and they are great but anyone have a link or tutorial to get me going on this specific task?

(Learning to crawl again)

Roy Lawson
ro*@xeon.tv

Nov 20 '05 #5

P: n/a
Keep on walking ;-)
"Roy Lawson" <ro*@xeon.tv> schrieb im Newsbeitrag news:06****************************@phx.gbl...
For what I am doing, there are no constraints on the table
(single table only) so there is only 1 DataTable object in
my DataSet. I set it up this way (1 table w/o relations)
just so I could get it going (crawl before walking).

But, your explanation was very helpful and I think with
that I can figure out programaticly how to proceed. I
suspect I need to focus on the DataColumns collection when
it comes to navigating the DataTable within my DataSet.

My code is on my laptop ... I will submit an update to
this post after I figure it out so that others can learn
to walk with me :-)

Thanks!

-Roy

-----Original Message-----
Roy,

maybe it helps you if you imagine the following:

The DataSet object contains a collection of zero or more

DataTable objects, each of which is an in-memory
representation of a single table. The structure of a
particular DataTable is defined by the DataColumns
collection, which enumerates the columns in a particular
table, and the Constraint collection, which enumerates any
constraints on the table. Together, these two collections
make up the table schema. A DataTable also contains a
DataRows collection, which contains the actual data in the
DataSet.

The DataSet contains a DataRelations collection. A

DataRelation object allows you to create associations
between rows in one table and rows in another table. The
DataRelations collection enumerates a set of DataRelation
objects that define the relationships between tables in
the DataSet. For example, consider a DataSet that contains
two related tables: an Employees table and a Projects
table. In the Employees table, each employee is
represented only once and is identified by a unique
EmployeeID field. In the Projects table, an employee in
charge of a project is identified by the EmployeeID field,
but can appear more than once if that employee is in
charge of multiple projects. This is an example of a one-
to-many relationship; you would use a DataRelation object
to define this relationship.

Excerpt from the book "MCAD/MCSD Training Kit-Developing

Windows-Based Applications with Microsoft Visual
Basic .NET and Microsoft Visual C# ..NET" which I can
truly recommend.



If you for example have a table "myTable" in a

DataSet "myDataSet" and you want to bind the field "ID" of
the first row of the table to a TextBox named TextBox1 do
the following:



TextBox1.Text = myDataSet.Tables("myTable").Rows(0).Item

("ID").ToString



I hope this gives you the general idea. Always visualize

the collections in the ADO.NET model.



Best regards

Daniel Walzenbach

"Roy Lawson" <ro*@xeon.tv> schrieb im Newsbeitrag

news:c4**************************@posting.google.c om...
I am having no problems connecting to a DB, creating a DataAdapter, and creating a dataset...and connecting to the data. Using the builtin data objects to do all this.

My only problem now is navigating through the data. I can get the data into a datagrid without any problems, but I want the data to show up in textboxes and use some sort of move next, move previous, move last, etc (like in VB6) command to navigate the data (using buttonX_click). I have been using the learnvisualstudio.net videos and they are great but anyone have a link or tutorial to get me going on this specific task?

(Learning to crawl again)

Roy Lawson
ro*@xeon.tv

Nov 20 '05 #6

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