查询在 ASP.net 中不起作用
本文关键字:不起作用 net ASP 查询 | 更新日期: 2023-09-27 18:35:46
如果查询结果是 = 到 btn1,我试图隐藏此按钮。命令参数。
查询有效,因为我已经测试过它,但整个解决方案不起作用。
如果我更换
myCommand.ExecuteScalar().ToString()
在查询结果的 if
语句中,该按钮处于隐藏状态。
我看了好几次,但找不到任何问题。谢谢。
protected void ListView1_ItemDataBound(object sender, ListViewItemEventArgs e)
{
Button btn1 = (Button)e.Item.FindControl("addFollowerButton");
// request Query string
var querystring = Request.QueryString["ProjectId"];
string connectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
string select = "Select ProfileId from Project_Follower Where ProjectId = @ProjectId";
using (SqlConnection myConnection = new SqlConnection(connectionString))
{
myConnection.Open();
SqlCommand myCommand = new SqlCommand(select, myConnection);
myCommand.Parameters.AddWithValue("@ProjectId", querystring);
myCommand.ExecuteScalar();
if (myCommand.ExecuteScalar().ToString() == btn1.CommandArgument.ToString())
{
Button hdn = (Button)e.Item.FindControl("addFollowerButton");
btn1.Visible = false;
}
}
}
您只需执行一次.ExecuteScalar()
调用!获取结果(类型 object
),然后检查以确保它没有null
,如果是,请对其调用 .ToString()
并与要检查的其他字符串进行比较:
using (SqlConnection myConnection = new SqlConnection(connectionString))
{
myConnection.Open();
SqlCommand myCommand = new SqlCommand(select, myConnection);
myCommand.Parameters.AddWithValue("@ProjectId", querystring);
object result = myCommand.ExecuteScalar();
if (result != null && result.ToString().Equals(btn1.CommandArgument.ToString()))
{
Button hdn = (Button)e.Item.FindControl("addFollowerButton");
btn1.Visible = false;
}
}