本文讨论如何使用 ADO.NET 检索 Microsoft Excel 工作簿中的数据、修改现有工作簿中的数据或将数据添加至新的工作簿中。要通过 ADO.NET 访问 Excel 工作簿，您可以使用 Jet OLE DB 提供程序；本文提供了您所需要的信息，以便您可以在 Excel 充当目标数据源时使用 Jet OLE DB 提供程序。
Microsoft Jet 数据库引擎可以通过可安装的索引顺序访问方法 (ISAM) 驱动程序，访问格式为其他数据库文件（例如 Excel 工作簿）的数据。要打开 Microsoft Jet 4.0 OLE DB 提供程序所支持的外部格式，请在连接的扩展属性中指定数据库类型。Jet OLE DB 提供程序对于 Microsoft Excel 工作簿支持下列数据库类型：
如果 Jet OLE DB 提供程序能够使用另外的数据源，请将该数据源中的数据导出到 Excel 工作簿中。可通过 Jet OLE DB 提供程序以这种方式使用的数据源包括：文本文件、Microsoft Access 数据库，当然也包括其他 Excel 工作簿。使用单个 INSERT INTO 命令，您可以将其他表/查询中的数据导出到您的工作簿中：
INSERT INTO [Sheet1$] IN 'C:\Book1.xls' 'Excel 8.0;' SELECT * FROM MyTable"
INSERT INTO 要求目标表（或工作表）已存在，并且数据已附加到目标表中。
您还可以使用 SELECT..INTO 将您的表/查询导出到工作簿中：
SELECT * INTO [Excel 8.0;Database=C:\Book1.xls].[Sheet1] FROM [MyTable]
Private m_sConn1 As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=C:\ExcelData1.xls;" & _
"Extended Properties=""Excel 8.0;HDR=YES"""
Private m_sConn2 As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=C:\ExcelData2.xls;" & _
"Extended Properties=""Excel 8.0;HDR=YES"""
Private m_sNorthwind = _
"C:\Program Files\Microsoft Office\Office10\Samples\Northwind.mdb"
Private m_sAction As String
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
RadioButton1.Text = "Create_Workbook"
RadioButton2.Text = "Retrieve_Records"
RadioButton3.Text = "Add_Records"
RadioButton4.Text = "Update_Records"
RadioButton5.Text = "Update_Individual_Cells"
RadioButton6.Text = "Use_External_Source"
Button1.Text = "Go!"
End Sub
Private Sub RadioButtons_Click(ByVal sender As Object, ByVal e As System.EventArgs) _
Handles RadioButton1.Click, RadioButton2.Click, RadioButton3.Click, _
RadioButton4.Click, RadioButton5.Click, RadioButton6.Click
m_sAction = sender.Text'Store the text for the selected radio button
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Try
' Call the associated routine to add/update/modify the workbook.
Select Case m_sAction
Case "Create_Workbook" : Create_Workbook()
Case "Retrieve_Records" : Retrieve_Records()
Case "Add_Records" : Add_Records()
Case "Update_Records" : Update_Records()
Case "Update_Individual_Cells" : Update_Individual_Cells()
Case "Use_External_Source" : Use_External_Source()
End Select
Catch ex As OleDbException
Dim er As OleDbError
For Each er In ex.Errors
MsgBox(er.Message)
Next
Catch ex2 As System.InvalidOperationException
MsgBox(ex2.Message)
End Try
End Sub
Public Sub Create_Workbook()
' If the workbooks already exist, prompt to delete.
Dim answer As MsgBoxResult
If Dir("C:\ExcelData1.xls") <> "" Or Dir("C:\ExcelData2.xls") <> "" Then
answer = MsgBox("Delete existing workbooks (C:\ExcelData1.xls and " & _
"C:\ExcelData2.xls)?", MsgBoxStyle.YesNo)
If answer = MsgBoxResult.Yes Then
If Dir("C:\ExcelData1.xls") <> "" Then Kill("C:\ExcelData1.xls")
If Dir("C:\ExcelData2.xls") <> "" Then Kill("C:\ExcelData2.xls")
Else
Exit Sub
End If
End If
'==========================================================================
' Create a workbook with a table named EmployeeData. The table has 3
' fields: ID (char 255), Name (char 255) and Birthdate (date).
'==========================================================================
Dim conn As New OleDbConnection()
conn.ConnectionString = m_sConn1
conn.Open()
Dim cmd1 As New OleDbCommand()
cmd1.Connection = conn
cmd1.CommandText = "CREATE TABLE EmployeeData (Id char(255), Name char(255), BirthDate date)"
cmd1.ExecuteNonQuery()
cmd1.CommandText = "INSERT INTO EmployeeData (Id, Name, BirthDate) values ('AAA', 'Andrew', '12/4/1955')"
cmd1.ExecuteNonQuery()
conn.Close()
'==========================================================================
' Create a workbook with a table named InventoryData. The table has 3
' fields: Product (char 255), Qty (float) and Price (currency).
'==========================================================================
conn.ConnectionString = m_sConn2
conn.Open()
Dim cmd2 As New OleDbCommand()
cmd2.Connection = conn
cmd2.CommandText = "CREATE TABLE InventoryData (Product char(255), Qty float, Price currency)"
cmd2.ExecuteNonQuery()
cmd2.CommandText = "INSERT INTO InventoryData (Product, Qty, Price) values ('Cola', 200, 1.35)"
cmd2.ExecuteNonQuery()
cmd2.CommandText = "INSERT INTO InventoryData (Product, Qty, Price) values ('Chips', 550, 0.89)"
cmd2.ExecuteNonQuery()
conn.Close()
' NOTE: You can ALTER and DROP tables in a similar fashion.
End Sub
Public Sub Retrieve_Records()
'==========================================================
'Use a DataReader to read data from the EmployeeData table.
'==========================================================
Dim conn1 As New System.Data.OleDb.OleDbConnection(m_sConn1)
conn1.Open()
Dim cmd1 As New System.Data.OleDb.OleDbCommand("Select * From [EmployeeData$]", conn1)
Dim rdr As OleDbDataReader = cmd1.ExecuteReader
Debug.WriteLine(vbCrLf & "EmployeeData:" & vbCrLf & "=============")
Do While rdr.Read()
Debug.WriteLine(System.String.Format("{0,-10}{1, -15}{2}", _
rdr.GetString(0), rdr.GetString(1), _
rdr.GetDateTime(2).ToString("d")))
Loop
rdr.Close()
conn1.Close()
'========================================================
'Use a DataSet to read data from the InventoryData table.
'========================================================
Dim conn2 As New OleDbConnection(m_sConn2)
Dim da As New OleDbDataAdapter("Select * From [InventoryData$]", conn2)
Dim ds As DataSet = New DataSet()
da.Fill(ds)
Debug.WriteLine(vbCrLf & "InventoryData:" & vbCrLf & "==============")
Dim dr As DataRow
For Each dr In ds.Tables(0).Rows'Show results in output window
Debug.WriteLine(System.String.Format("{0,-15}{1, -6}{2}", _
dr("Product"), dr("Qty"), dr("Price")))
Next
conn2.Close()
End Sub
Public Sub Add_Records()
'==========================================================================
' Run an INSERT INTO command to add new records to the workbook.
'==========================================================================
Dim conn1 As New System.Data.OleDb.OleDbConnection(m_sConn1)
conn1.Open()
Dim cmd As New System.Data.OleDb.OleDbCommand()
cmd.Connection = conn1
cmd.CommandText = "INSERT INTO [EmployeeData$] (ID, Name, BirthDate) values ('CCC', 'Charlie', '10/14/48')"
cmd.ExecuteNonQuery()
cmd.CommandText = "INSERT INTO [EmployeeData$] (ID, Name, BirthDate) values ('DDD', 'Deloris', '7/19/98')"
cmd.ExecuteNonQuery()
conn1.Close()
'====================================================================
'Use the InsertCommand object to add new records to the InventoryData
'table.
'====================================================================
Dim conn2 As New OleDbConnection(m_sConn2)
Dim da As New OleDbDataAdapter("Select * From [InventoryData$]", conn2)
Dim ds As DataSet = New DataSet()
da.Fill(ds, "MyExcelTable")
' Generate the InsertCommand and add the parameters for the command.
da.InsertCommand = New OleDbCommand( _
"INSERT INTO [InventoryData$] (Product, Qty, Price) VALUES (?, ?, ?)", conn2)
da.InsertCommand.Parameters.Add("@Product", OleDbType.VarChar, 255, "Product")
da.InsertCommand.Parameters.Add("@Qty", OleDbType.Double).SourceColumn = "Qty"
da.InsertCommand.Parameters.Add("@Price", OleDbType.Currency).SourceColumn = "Price"
' Add two new records to the dataset.
Dim dr As DataRow
dr = ds.Tables(0).NewRow
dr("Product") = "Bread" : dr("Qty") = 390 : dr("Price") = 1.89 : ds.Tables(0).Rows.Add(dr)
dr = ds.Tables(0).NewRow
dr("Product") = "Milk" : dr("Qty") = 99 : dr("Price") = 2.59 : ds.Tables(0).Rows.Add(dr)
' Apply the dataset changes to the actual data source (the workbook).
da.Update(ds, "MyExcelTable")
conn2.Close()
End Sub
Public Sub Update_Records()
'==========================================================================
' Run an UPDATE command to change a record in the EmployeeData
' table.
'==========================================================================
Dim conn1 As New System.Data.OleDb.OleDbConnection(m_sConn1)
conn1.Open()
Dim cmd As New System.Data.OleDb.OleDbCommand()
cmd.Connection = conn1
cmd.CommandText = "UPDATE [EmployeeData$] " & _
"SET NAME = 'Aaron', BirthDate = '5/4/1975' WHERE ID = 'AAA'"
cmd.ExecuteNonQuery()
conn1.Close()
'====================================================================
' Use the UpdateCommand object to modify records in the InventoryData
' table.
'====================================================================
Dim conn2 As New OleDbConnection(m_sConn2)
Dim da As New OleDbDataAdapter("Select * From [InventoryData$]", conn2)
Dim ds As DataSet = New DataSet()
da.Fill(ds, "MyInventoryTable")
' Generate the UpdateCommand and add the parameters for the command.
da.UpdateCommand = New OleDbCommand( _
"UPDATE [InventoryData$] SET Qty = ?, Price=? WHERE Product = ?", conn2)
da.UpdateCommand.Parameters.Add("@Qty", OleDbType.Numeric).SourceColumn = "Qty"
da.UpdateCommand.Parameters.Add("@Price", OleDbType.Currency).SourceColumn = "Price"
da.UpdateCommand.Parameters.Add("@Product", OleDbType.VarChar, 255, "Product")
' Update the first two records.
ds.Tables(0).Rows(0)("Qty") = 1000
ds.Tables(0).Rows(0)("Price") = 10.1
ds.Tables(0).Rows(1)("Qty") = 2000
ds.Tables(0).Rows(1)("Price") = 20.2
' Apply the dataset changes to the actual data source (the workbook).
da.Update(ds, "MyInventoryTable")
conn2.Close()
End Sub
Public Sub Update_Individual_Cells()
'==========================================================================
' Update individual cells on the EmployeeData worksheet;
' specifically, cells F3, G3, and I4 are modified.
'==========================================================================
' NOTE: The connection string indicates that the table does *NOT*
' have a header row.
Dim conn As New System.Data.OleDb.OleDbConnection(m_sConn1.Replace("HDR=YES", "HDR=NO"))
conn.Open()
Dim cmd As New System.Data.OleDb.OleDbCommand()
cmd.Connection = conn
cmd.CommandText = "UPDATE [EmployeeData$F3:G3] SET F1 = 'Cell F3', F2 = 'Cell G3'"
cmd.ExecuteNonQuery()
cmd.CommandText = "UPDATE [EmployeeData$I4:I4] SET F1 = 'Cell I4'"
cmd.ExecuteNonQuery()
conn.Close()
End Sub
Public Sub Use_External_Source()
' Open a connection to the sample Northwind Access database.
Dim conn As New System.Data.OleDb.OleDbConnection( _
"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & m_sNorthwind & ";")
conn.Open()
Dim cmd As New System.Data.OleDb.OleDbCommand()
cmd.Connection = conn
'=======================================================================
' Run an INSERT..INTO command on the Northwind database to append
' the records from a table/query to an existing table in the Excel
' workbook.
'=======================================================================
cmd.CommandText = "INSERT INTO [EmployeeData$] IN 'C:\ExcelData1.xls' 'Excel 8.0;'" & _
"SELECT EmployeeID AS ID, FirstName AS Name, BirthDate FROM Employees"
cmd.ExecuteNonQuery()
'==========================================================================
' Run a SELECT..INTO command on the Northwind database to insert
' all the records from a table/query into a new sheet in the Excel
' workbook.
'==========================================================================
cmd.CommandText = "SELECT * INTO [Excel 8.0;Database=C:\ExcelData2.xls].[ProductSales]" & _
"FROM [Product Sales for 1997]"
cmd.ExecuteNonQuery()
conn.Close()
End Sub
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