Question

我一直在互联网上寻找一种从sql数据表中显示特定内容的方法。我希望我可以根据Id列值显示Content列。 alt text http://photos-h.ak.fbcdn.net/hphotos-ak-snc3/hs031.snc3/11852_1241994617732_1465331687_655971_2468696_n.jpg

Answer 1

如果您想从一个记录中只有一个值，则可以使用SqlCommand类的ExecuteScalar方法：

string title = null;
using (SqlConnection conn = new SqlConnection("your-connection-string"))
using (SqlCommand cmd = new SqlCommand(
    "select ContentTitle from {put table name here} where id = 4", conn))
{
    conn.Open();
    title = (string)conn.ExecuteScalar();
}

if (!string.IsNullOrEmpty(title))
{
    // assign title to suitable asp.net control property
}

如果您希望能够针对各种ID执行此操作，不要只连接新的sql字符串。我将重复一遍：不要只是连接一个新的sql字符串。改为使用参数：

string title = null;
using (SqlConnection conn = new SqlConnection("your-connection-string"))
using (SqlCommand cmd = new SqlCommand(
    "select ContentTitle from {put table name here} where id = @id", conn))
{
    SqlParameter param  = new SqlParameter();
    param.ParameterName = "@id";
    param.Value = yourIdGoesHere;
    cmd.Parameters.Add(param);

    conn.Open();
    title = (string)conn.ExecuteScalar();
}

if (!string.IsNullOrEmpty(title))
{
    // assign title to suitable asp.net control property
}

<强>更新
样本aspx页面。首先是一些标记（假设该文件名为example.aspx）：

<body>
   <form id="Form1" runat="server">
      Title: <asp:Label id="_titleLabel" 
                 Text="{no title assigned yet}" 
                 runat="server"/>
   </form>
</body>

...并且在代码隐藏中（将被称为example.aspx.cs;为简单起见，我仅包含了Page_Load事件）：

protected void Page_Load(object sender, EventArgs e)
{
    int id;
    try
    {
        if (int.TryParse(Request.QueryString["id"], out id))
        {
            _titleLabel.Text = GetContentTitle(id);
        }
        else
        {
            _titleLabel.Text = "no id given; cannot look up title";
        }
    }
    catch (Exception ex)
    {
        // do something with the exception info
    }
}

private static string GetContentTitle(int id)
{ 
    using (SqlConnection conn = new SqlConnection("your-connection-string"))
    using (SqlCommand cmd = new SqlCommand(
        "select ContentTitle from {put table name here} where id = @id", conn))
    {
        SqlParameter param  = new SqlParameter();
        param.ParameterName = "@id";
        param.Value = yourIdGoesHere;
        cmd.Parameters.Add(param);

        conn.Open();
        return (string)conn.ExecuteScalar();
    }
}

免责声明：代码直接写入答案窗口而未经过测试（我现在无法访问开发环境）因此可能存在错误

从microsoft sql express数据表中显示asp.net网页上的特定数据

1 个答案: