干得好：
如何：参考 ASP.NET 母版页内容 http://msdn.microsoft.com/en-us/library/xxwa0ff0.aspx
从文章看来，
If Master.SQLerror = Nothing Then
InternalSQLErrLabel.Text = ("No Errors Reported")
End If
应该为你工作。
只需确保按照描述添加 MasterType 指令，否则您可能会收到类型转换错误。 （或者您可以使用母版页类型的变量而不是 Master，正如 daRoBBie 在他的回答中建议的那样。）
我创建了一个测试网站只是为了测试这一点，并且它有效。这是该网站的完整来源:
Site1.Master:
<%@ Master Language="VB" AutoEventWireup="false" CodeBehind="Site1.master.vb" Inherits="WebApplication1.Site1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
This is the Master Page content.
<asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
</asp:ContentPlaceHolder>
</div>
</form>
</body>
</html>
Site1.Master.vb:
Public Partial Class Site1
Inherits System.Web.UI.MasterPage
Private _SQLerror As String
Public Property SQLerror() As String
Get
Return _SQLerror
End Get
Set(ByVal value As String)
_SQLerror = String.Empty
End Set
End Property
End Class
WebForm1.aspx:
<%@ Page Title="" Language="vb" AutoEventWireup="false" MasterPageFile="~/Site1.Master"
CodeBehind="WebForm1.aspx.vb" Inherits="WebApplication1.WebForm1" %>
<%@ MasterType VirtualPath="~/Site1.Master" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
This is the Content Page content.
<asp:Label ID="InternalSQLErrLabel" runat="server" Text="Label"></asp:Label>
</asp:Content>
WebForm1.aspx.vb:
Public Partial Class WebForm1
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Master.SQLerror = Nothing Then
InternalSQLErrLabel.Text = ("No Errors Reported")
End If
End Sub
End Class
