... 5.3 Converting a DataReaderto a DataSet
Problem
You need to transfer data from a DataReaderto a DataSet.
Solution
Create a DataTable schema in the destination DataSet using the schema information ... method that converts a
DataReader to a DataSet, this method is declared protected and cannot be accessed
(unless you write a custom DataAdapter). There is no built-in mechanism for converting ... the GetSchemaTable( ) method of the DataReader. Then, use the GetData( )
method of the DataReaderto load each row of data into an array of objects, and add it to
the DataTable using the Add(...
... aren’t able to first reduce the num-
ber of ADO.NET-managed rows, you might wish to consider alternatives to LINQ to DataSet.
LINQ to Entities, discussed in Chapter 19, “Using LINQ to Entities,” ... DataAdapter to load data, call its Fill method before using LINQ to extract data.
Note
The DataAdapter object’s Fill method loads all requested data into local DataSet memory.
If the tables you need to ... = From cu In Customer.AsEnumerable()
Select CustomerName = cu.Field(Of String)("FullName")
Order By CustomerName
Dwonloaded from: iDATA.ws
Chapter 18
Using LINQ to DataSet
After completing...
... datab_0; datab_1;
datab_2 là các số 11 bit có dấu;
2. KHỐI CONVERT YCRCB TO RGB
2.1SƠ ĐỒ KHỐI
Hình 11.1: Sơ đồ của khối Convert YCrCb to RGB
Tên Mô tả
CLK
Xung clock 27Mhz từ kit DE2.
RESET Reset ... oRequest = ( ( H_Cont >= H_BLANK && H_Cont < H_TOTAL )
&& ( V_Cont>=V_BLANK && V_Cont<V_TOTAL ) );
//tính to n vị trí X,Y của Pixel trong frame (X : vị trí pixel ... ;
Do các hệ số có dạng thập phân, trong khi đó các phép to n của phần cứng được tổng
hợp chỉ thực hiện trên số nguyên nên khi làm tròn và tính to n thì sai số khá lớn, vì vậy ta phải
nhân biểu thức...
... Team LiB ]
Recipe 5.2 Copying Tables from One DataSetto Another
Problem
You need to copy an existing schema and data from one DataSetto another.
Solution
Use one of the following techniques: ...
the Orders table is bound to a data grid on the form.
Copy Button.Click
Creates a destination DataSet and copies the schema and specified data into it
from the source DataSet created in the Form.Load ... source DataSet are copied to the
destination. This is accomplished by iterating over the collection of tables in the source
DataSet and using the Copy( ) method of each DataTable object to copy...
... Converting a DataSetto an ADO Recordset
Problem
You need toconvert a DataSetto an ADO Recordset so that you can use it in a legacy
application.
Solution
You must persist the DataSetto ... used to transform the XML document output by the DataSet
into an ADO Recordset XML document.
The sample code contains one event handler and one method:
Go Button.Click
Converts the DataSetto ... A DataReader accesses the schema information for the data toconvert
using the GetSchemaTable( ) method. This information is mapped to and
added to the ADO Recordset XML document.
3. The DataSet...
... File That Shows Changes Made to a DataSet
Problem
When you use the GetXML( ) method of the DataSet, you may see only the current
values in the DataSet. You want to get the original values and ... modifications made to a
DataSet.
The sample code contains two event handlers and a single method:
Form.Load
Sets up the sample by loading the Categories table from Northwind into a DataSet
and ... written for the DataSet by specifying an
XmlWriteMode of DiffGram when calling the WriteXml( ) method of the DataSet. The
GetXml( ) method cannot be used to generate a DiffGram. A DataSet can be...
... library stocked with tools for everything
from sending e-mail to encrypting a password. To master ASP.NET, you need to learn about
each of these ingredients.
This book covers all these topics from ... learning curve. Not only do you need to learn how to use an advanced design tool
(Visual Studio) and a toolkit of objects (the .NET Framework), you also need to master a pro-
gramming language ... sometimes used in a narrow sense to refer to the portion of the .NET class library
used to design web pages. On the other hand, ASP.NET also refers to the whole topic of .NET
web applications,...
...
Create Button.Click
This event handler calls the CreateData( ) method to add random data to the
DataSet.
Modify Button.Click
This event handler makes random changes to the data in the DataSet: ... CreateData( ) method is called to create new data.
• The UpdateData( ) method is called to update all of the changes made to the
DataSet with the data source.
Delete Button.Click
This event handler ... updating a DataSet with a many -to- one relationship is shown in
data source.
Refresh Button.Click
This event handler clears all data from the DataSet. LoadData( ) is then called to
load all...
...
[ Team LiB ]
Recipe 8.6 Using XPath to Query Data in a DataSet
Problem
You need to use an XPath expression to extract certain rows from a DataSet.
Solution
Use SelectSingleNode( ) ... to access the XmlDataDocument to perform certain
functionality more conveniently than could be accomplished using the DataSet directly.
To execute an XPath query against the contents of a DataSet, ... by creating a DataSet containing the Orders table and Order
Details table from Northwind and a nested relation between the two tables.
Go Button.Click
Executes an XPath query to retrieve the...
...
private void writeSchemaButton_Click(object sender, System.EventArgs e)
{
DataSet ds = new DataSet( );
SqlDataAdapter da;
// Fill the Order table and add it to the DataSet.
da = new SqlDataAdapter("SELECT ...
try
{
// Read the schema into the DataSet.
DataSet ds = new DataSet( );
ds.ReadXmlSchema(xtr);
// Bind the default view of the Orders table to the grid.
resultDataGrid.DataSource ... id="NewDataSet" xmlns=""
[ Team LiB ]
Recipe 8.1 Using XSD Schema Files to Load and Save a DataSet Structure
Problem
You need to create an XSD schema from a DataSet and...