ASP.NET 从 SQL 切换到 Access DB 后，我无法让我的数据源/gridview 正常工作

Question

我有一个即将到期的学校项目，它是一个 ASP.NET 中的网络应用程序，我认为我已经完成并使用本地 MySQL 数据库按预期工作。我的教授最近指示我们将我们的数据库更改为 MS Access，我已经成功地将所有转换都作为我的课程之一。有问题的类从我的 DB 表中获取注册的人，并将其列在网格视图中，并带有过滤器并将 DOB 转换为年龄。我将包含我的代码以及错误的屏幕截图。环顾四周，我发现您可以配置 SqlDataSource 以使用访问数据库，因此我按照步骤操作，这是我现在遇到的错误； '在应用程序配置中找不到连接名称'newregDBConnectionString.System.Data.OleDb'或连接字符串为空。'

谁能帮我看看我哪里出错了？提前致谢！

我的 Web.config；

<add name="newregDBConnectionString" connectionString="Provider=Microsoft.ACE.OLEDB.12.0;
 Data Source=C:\Users\Alex\Documents\Database1.accdb"
 providerName="System.Data.OleDb" />

我为使用访问数据库配置 SqlDataSource 所遵循的步骤；

<asp:SqlDataSource 
ID="source"
runat ="server" 
ConnectionString ="<%$ ConnectionStrings:newregDBConnectionString %>"
ProviderName ="<%$ ConnectionStrings:newregDBConnectionString.System.Data.OleDb %>"
SelectCommand= "SELECT firstname, childID, dob, DATEDIFF(hour, dob, GETDATE()) / 8766 AS age FROM children ORDER BY age"   />

我试图在其中显示 gridview 的 C# 代码；

namespace Coursework
{
public partial class Testy1 : System.Web.UI.Page
{
    //create a datasource
    SqlDataSource source = new SqlDataSource();     

    protected void Page_Load(object sender, EventArgs e)
    {
        //always set some defaults for the datasource
        source.ID = "source1";
        source.ConnectionString = ConfigurationManager.ConnectionStrings["newregDBConnectionString"].ConnectionStr‌ing;
        source.SelectCommand = "SELECT firstname, childID, dob, DATEDIFF(hour, dob, GETDATE()) / 8766 AS age FROM children ORDER BY age";

        if (!IsPostBack)
        {
            //bind the grid
            GridView1.DataSource = source;
            GridView1.DataBind();
        }
    }       
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        //the new database query, now with where clause
        source.SelectCommand = "SELECT firstname, childID, dob, DATEDIFF(hour, dob, GETDATE()) / 8766 AS age FROM children WHERE (DATEDIFF(hour, dob, GETDATE()) / 8766 BETWEEN @start AND @end) ORDER BY age";

        //get the end age from the dropdown and cast as int
        int end = Convert.ToInt32(DropDownList1.SelectedValue);

        //get the start int for the filter
        int start = end - 2;

        //if the filter is resetted, make sure the query returns all ages
        if (end == 5)
        {
            start = 5;
            end = 99;
        }

        //replace the parameters in the query
        source.SelectParameters.Add("start", start.ToString());
        source.SelectParameters.Add("end", end.ToString());

        //rebind the grid
        GridView1.DataSource = source;
        GridView1.DataBind();
    }

    protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
    {

    }

    protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        string childID = GridView1.DataKeys[e.RowIndex].Value.ToString();
        string deleteSql = "DELETE FROM Children WHERE childID = @childID; ";
        using (var con = new OleDbConnection(ConfigurationManager.ConnectionStrings["newregDBConnectionString"].ConnectionStr‌​ing))
        using (var cmd = new OleDbCommand(deleteSql, con))
        {
            cmd.Parameters.Add("@childID", OleDbType.VarChar).Value = childID;
            con.Open();
            int deleted = cmd.ExecuteNonQuery();
        }

        GridView1.DataSource = source;
        GridView1.DataBind();
    }

    protected void backBtn_Click(object sender, EventArgs e)
    {
        Response.Redirect("Registration.aspx");
    }
}

}

Answer 1

SqlDataSource 中的ProviderName 属性值格式错误：

ProviderName="<%$ ConnectionStrings:newregDBConnectionString.System.Data.OleDb %>"

从MSDN documentation，ConnectionStrings:newregDBConnectionString.providerName数据源绑定中的providerName属性引用web.config连接字符串元素中的providerName属性值。因此，您应该保持 providerName 属性不变：

<asp:SqlDataSource ID="source" runat="server" 
ConnectionString="<%$ ConnectionStrings:newregDBConnectionString %>"
ProviderName="<%$ ConnectionStrings:newregDBConnectionString.providerName %>"
SelectCommand="SELECT firstname, childID, dob, DATEDIFF(hour, dob, GETDATE()) / 8766 AS age FROM children ORDER BY age" />

或直接使用提供者名称：

ProviderName="System.Data.OleDb"

相关问题（查看providerName 属性如何以类似方式使用）：

ASP .NET - Configure SQLDataSource to use MySQL .NET Connector