5.11. Exporting the Results of a Query as a String
Problem
You need to export the results of a query to a string in a manner similar to
the GetString( )
method of the ADO
Recordset
.
Solution
Write a routine to mimic the functionality of the ADO
Recordset
’s GetString( )
method.
The sample code contains an event handler and a method:
- Go
Button.Click
Sets up the sample by creating a
DataTable
containing the Orders table from Northwind. TheGetString( )
method in this solution is called to convert theDataTable
into a string similar to one that is generated by theGetString( )
method of the ADORecordset
. The string is displayed in a text box on the form.GetString( )
This method mimics the functionality of the
GetString( )
method of the ADORecordset
. The method iterates over the collection of rows and columns in the table appending the field values to a string. Null values are replaced as specified and column and row delimiters are applied.
The C# code is shown in Example 5-13.
Example 5-13. File: AdoGetStringForm.cs
// Namespaces, variables, and constants using System; using System.Configuration; using System.Text; using System.Data; using System.Data.SqlClient; // Table name constants private const String ORDERS_TABLE = "Orders"; // . . . private void goButton_Click(object sender, System.EventArgs e) { // Fill the Order table. SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM Orders", ConfigurationSettings.AppSettings["Sql_ConnectString"]); DataTable dt = new DataTable(ORDERS_TABLE); ...
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