Binding a Combo Box to a DataReader

In This Topic

You can bind a combo box to a DataReader. A DataReader lets you access data in a read-only, forward-only way from a data source. Using a DataReader is often a quick way of returning results, as illustrated in the following example for populating results in a combo box.

Example

This example adds data to a combo cell from a data source.

C#	Copy Code
/// Set up a connection to the database. The database name is an example. string dbpath = "c:\\reader.mdb"; System.Data.OleDb.OleDbConnection dbConn = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;DATA SOURCE=" + dbpath); /// Open a connection and a SELECT command. dbConn.Open(); System.Data.OleDb.OleDbCommand dbCommand = new System.Data.OleDb.OleDbCommand("SELECT * FROM Table1", dbConn); /// Open a DataReader on that connection and command. System.Data.OleDb.OleDbDataReader dr = dbCommand.ExecuteReader(System.Data.CommandBehavior.CloseConnection); /// Loop through the rows returned by the reader. ArrayList al = new ArrayList(); while (dr.Read()) { al.Add(dr("Data")); } /// Populate combo box with data converted to strings. string[] s; s = al.ToArray(typeof(string)); FarPoint.Win.Spread.ComboBoxCellType cb = new FarPoint.Win.Spread.ComboBoxCellType(); cb.Items = s; fpSpread1.ActiveSheetView.Cells(0, 0).CellType = cb; /// Dispose connection. dbConn.Dispose();

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/// Set up a connection to the database. The database name is an example.
string dbpath = "c:\\reader.mdb";
System.Data.OleDb.OleDbConnection dbConn = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;DATA SOURCE=" + dbpath);
/// Open a connection and a SELECT command.
dbConn.Open();
System.Data.OleDb.OleDbCommand dbCommand = new System.Data.OleDb.OleDbCommand("SELECT * FROM Table1", dbConn);
/// Open a DataReader on that connection and command.
System.Data.OleDb.OleDbDataReader dr = dbCommand.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
/// Loop through the rows returned by the reader.
ArrayList al = new ArrayList();
while (dr.Read()) {
     al.Add(dr("Data"));
}
/// Populate combo box with data converted to strings.
string[] s;
s = al.ToArray(typeof(string));
FarPoint.Win.Spread.ComboBoxCellType cb = new FarPoint.Win.Spread.ComboBoxCellType();
cb.Items = s;
fpSpread1.ActiveSheetView.Cells(0, 0).CellType = cb;
/// Dispose connection.
dbConn.Dispose();

VB	Copy Code
' Set up a connection to the database. The database name is an example. Dim dbpath As String = "c:\reader.mdb" Dim dbConn As New System.Data.OleDb.OleDbConnection( _ "Provider=Microsoft.Jet.OLEDB.4.0;DATA SOURCE=" & dbpath) ' Open a connection and a SELECT command. dbConn.Open() Dim dbCommand As New System.Data.OleDb.OleDbCommand( _ "SELECT * FROM Table1", dbConn) ' Open a DataReader on that connection and command. Dim dr As System.Data.OleDb.OleDbDataReader = dbCommand.ExecuteReader(System.Data.CommandBehavior.CloseConnection) ' Loop through the rows returned by the reader. Dim al As New ArrayList() While dr.Read() al.Add(dr("Data")) End While ' Populate combo box with data converted to strings. Dim s As String() s = al.ToArray(GetType(String)) Dim cb As New FarPoint.Win.Spread.ComboBoxCellType cb.Items = s fpSpread1.ActiveSheetView.Cells(0, 0).CellType = cb ' Dispose connection. dbConn.Dispose()

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' Set up a connection to the database. The database name is an example.
Dim dbpath As String = "c:\reader.mdb"
Dim dbConn As New System.Data.OleDb.OleDbConnection( _
"Provider=Microsoft.Jet.OLEDB.4.0;DATA SOURCE=" & dbpath)
' Open a connection and a SELECT command.
dbConn.Open()
Dim dbCommand As New System.Data.OleDb.OleDbCommand( _
"SELECT * FROM Table1", dbConn)
' Open a DataReader on that connection and command.
Dim dr As System.Data.OleDb.OleDbDataReader = dbCommand.ExecuteReader(System.Data.CommandBehavior.CloseConnection)
' Loop through the rows returned by the reader.
Dim al As New ArrayList()
While dr.Read()
     al.Add(dr("Data"))
End While
' Populate combo box with data converted to strings.
Dim s As String()
s = al.ToArray(GetType(String))
Dim cb As New FarPoint.Win.Spread.ComboBoxCellType
cb.Items = s
fpSpread1.ActiveSheetView.Cells(0, 0).CellType = cb
' Dispose connection.
dbConn.Dispose()