Asp.net 从sql server中的单个字段填充标签

表中有一列包含消息，我希望此消息显示在标签中。这是我的代码，目前没有填充标签

Protected conString As String = ConfigurationManager.AppSettings("sqldirectory")
Dim cnn As New SqlConnection(conString)
    Dim cmd As New SqlCommand("select message from [database].[dbo].[table]")
    Dim dr As SqlDataReader

    Try
        cnn.Open()
        dr = cmd.ExecuteReader()
        lblMsg.Text = dr(0).ToString
    Catch ex As Exception
        dr = Nothing
    Finally
        cnn.Close()
    End Try

---

好的，在玩过之后，我想出了一个有效的方法

Protected conString As String = ConfigurationManager.AppSettings("sqldirectory")
Dim cnn As New SqlConnection(conString)
Dim cmd As New SqlCommand("select message from [database].[dbo].[table]", cnn)
Dim dr As SqlDataReader
Dim msg As String
Try
    cnn.Open()
    dr = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection)
    While dr.Read()
        msg = dr("message")
        lblMsg.Text = msg
    End While
Catch ex As Exception
    dr = Nothing
Finally
    cnn.Close()
End Try

---

好的，在玩过之后，我想出了一个有效的方法

Protected conString As String = ConfigurationManager.AppSettings("sqldirectory")
Dim cnn As New SqlConnection(conString)
Dim cmd As New SqlCommand("select message from [database].[dbo].[table]", cnn)
Dim dr As SqlDataReader
Dim msg As String
Try
    cnn.Open()
    dr = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection)
    While dr.Read()
        msg = dr("message")
        lblMsg.Text = msg
    End While
Catch ex As Exception
    dr = Nothing
Finally
    cnn.Close()
End Try

---

我在寻找其他东西时偶然发现了这个。有一种更简单的方法可以做到这一点

我很想创建一些通用的应用程序代码来实现这一点。在项目中创建app_code文件夹，并使用以下代码创建common.vb文件：

Imports Microsoft.VisualBasic
Imports System.Data.SqlClient
Imports System.Data

Namespace GetDBResult
Public Class DB
    Public Shared Function GetRecord(sql As String) As String
        Dim result As String
        Dim connection As New SqlConnection(ConfigurationManager.ConnectionStrings("YourConnectionString").ToString)
        connection.Open()

        Dim command As New SqlCommand(sql, connection)

        Try
            If command.ExecuteScalar IsNot System.DBNull.Value Then
                result = command.ExecuteScalar
            Else
                result = ""
            End If
        Catch ex As Exception
            Throw ex

        Finally
            connection.Close()
        End Try

        Return result
    End Function
    End Class
    End Namespace

从那里，您可以从任何vb代码中调用该函数，从而很容易从数据库中获取字段以将其分配给标签。详情如下:

    Dim sql as string = "your sql query which should return one row and column"
    label1.text = DB.GetRecord(sql)

节省了大量重新键入的时间

哦，记住在任何希望使用应用程序代码的vb中导入代码

    Imports GetDBResult

非常感谢,，

---

尼尔

我在寻找其他东西时偶然发现了这个。有一种更简单的方法可以做到这一点

我很想创建一些通用的应用程序代码来实现这一点。在项目中创建app_code文件夹，并使用以下代码创建common.vb文件：

Imports Microsoft.VisualBasic
Imports System.Data.SqlClient
Imports System.Data

Namespace GetDBResult
Public Class DB
    Public Shared Function GetRecord(sql As String) As String
        Dim result As String
        Dim connection As New SqlConnection(ConfigurationManager.ConnectionStrings("YourConnectionString").ToString)
        connection.Open()

        Dim command As New SqlCommand(sql, connection)

        Try
            If command.ExecuteScalar IsNot System.DBNull.Value Then
                result = command.ExecuteScalar
            Else
                result = ""
            End If
        Catch ex As Exception
            Throw ex

        Finally
            connection.Close()
        End Try

        Return result
    End Function
    End Class
    End Namespace

从那里，您可以从任何vb代码中调用该函数，从而很容易从数据库中获取字段以将其分配给标签。详情如下:

    Dim sql as string = "your sql query which should return one row and column"
    label1.text = DB.GetRecord(sql)

节省了大量重新键入的时间

哦，记住在任何希望使用应用程序代码的vb中导入代码

    Imports GetDBResult

非常感谢,， 尼尔