visual basic设计公用模板，连接数据库代码

以下是一个使用Visual Basic设计公用模板并连接数据库的示例代码： ```vbnet Imports System.Data.SqlClient Public Class DatabaseConnection Private connectionString As String = "你的数据库连接字符串" Public Function ConnectToDatabase() As SqlConnection Dim connection As New SqlConnection(connectionString) Try connection.Open() Return connection Catch ex As Exception MessageBox.Show("无法连接到数据库： " & ex.Message) Return Nothing End Try End Function Public Function ExecuteQuery(ByVal query As String) As SqlDataReader Dim connection As SqlConnection = ConnectToDatabase() If connection IsNot Nothing Then Dim command As New SqlCommand(query, connection) Return command.ExecuteReader() Else Return Nothing End If End Function Public Function ExecuteNonQuery(ByVal query As String) As Integer Dim connection As SqlConnection = ConnectToDatabase() If connection IsNot Nothing Then Dim command As New SqlCommand(query, connection) Return command.ExecuteNonQuery() Else Return -1 End If End Function End Class ``` 请将`你的数据库连接字符串`替换为实际的数据库连接字符串。这个类包含了连接到数据库、执行查询和执行非查询操作的方法。你可以根据需要在你的项目中使用这个类来连接数据库并执行相应的操作。