名字'"'在当前上下文中不存在

本文关键字：上下文 不存在 quot 名字 | 更新日期: 2023-09-27 17:50:43

我的代码中有几个错误。这些错误是:

  • 错误17名称'CommandType'在当前上下文中不存在
  • 错误18名称'SqlDbType'在当前上下文中不存在
  • 错误35名称"txtCity"在当前上下文中不存在

我希望你能帮助我了解这个错误，并告诉我如何修复它。

protected void btnSave_Click(object sender, EventArgs e)
{
    // create connectionstring and insert statment
    string connectionString = ConfigurationManager.ConnectionStrings["connectionString"].ConnectionString;
    string insertSql = " INSERT INTO UserInfo (UID, FN, LN, Password, RePass, Email, Country,State, City)" +
        " values (@UsrNme, @fnbox, @lnamebox, @passtxtbx1, @passtxtbx2, @emailbox, @DrDncoundrlst, @DropDownListSwestate, @citytxtbox)";
    // create SQL Connection
    SqlConnection con = new SqlConnection(connectionString);
    // create sql command and parameters
    SqlCommand cmd = new SqlCommand();
    cmd.Connection = con;
    cmd.CommandType = CommandType.text;
    cmd.CommandText = insertSql;
    SqlParameter UID = new SqlParameter("@UsrNme", SqlDbType.nvarchar, 50);
    UID.Value = txtUID.text.tostring();
    cmd.Parameters.Add(UID);
    SqlParameter FN = new SqlParameter("@fnbox", SqlDbType.varchar,25);
    cmd.Connection = con;
    FN.Value = txtfn.text.ToString();
    cmd.Parameters.Add(FN);

    SqlParameter LN = new SqlParameter("@lnamebox", SqlDbType.varchar, 25);
    cmd.Connection = con;
    LN.Value = txtLN.text.ToString();
    cmd.Parameters.Add(LN);
    SqlParameter Password = new SqlParameter("@passtxtbx1", SqlDbType.varchar, 25);
    cmd.Connection = con;
    Password.Value = txtPassword.text.ToString();
    cmd.Parameters.Add(Password);

    SqlParameter RePass = new SqlParameter("@passtxtbx2", SqlDbType.varchar, 25);
    cmd.Connection = con;
    RePass.Value = txtRePass.text.ToString();
    cmd.Parameters.Add(RePass);

    SqlParameter Email = new SqlParameter("@emailbox", SqlDbType.varchar, 25);
    cmd.Connection = con;
    Email.Value = txtEmail.text.ToString();
    cmd.Parameters.Add(Email);
    SqlParameter Country = new SqlParameter("@DrDncoundrlst", SqlDbType.varchar, 25);
    cmd.Connection = con;
    Country.Value = txtCountry.text.ToString();
    cmd.Parameters.Add(Country);
    SqlParameter State = new SqlParameter("@DropDownListSwestate", SqlDbType.varchar, 25);
    cmd.Connection = con;
    State.Value = txtState.text.ToString();
    cmd.Parameters.Add(State);
    SqlParameter City = new SqlParameter("@citytxtbox", SqlDbType.varchar, 25);
    cmd.Connection = con;
    City.Value = txtCity.text.ToString();
    cmd.Parameters.Add(City);
    try
    {
        con.Open();
        cmd.ExecuteNonQuery();
        lblmsg.Text = "You already complete your registration process";
    }
    catch (SqlException ex)
    {
        string errorMessage = "error in registration user";
        errorMessage += ex.Message;
        throw new Exception(errorMessage);
    }
    finally
    {
        con.Close();
    }
}

名字'"'在当前上下文中不存在

你可能把事情弄得太复杂了。试试下面的代码…

var connection = new SqlConnection(connectionString);
var cmd = new SqlCommand(insertSql, connection);
cmd.Parameters.AddWithValue("@UsrNme", txtUID.Text.ToString());
cmd.Parameters.AddWithValue("@fnbox", txtfn.Text.ToString());
cmd.Parameters.AddWithValue("@lnamebox", txtLN.Text.ToString());
cmd.Parameters.AddWithValue("@passtxtbx1", txtPassword.Text.ToString());
cmd.Parameters.AddWithValue("@passtxtbx1", txtPassword.Text.ToString());
cmd.Parameters.AddWithValue("@passtxtbx2", txtRePass.Text.ToString());
cmd.Parameters.AddWithValue("@emailbox", txtEmail.Text.ToString());
cmd.Parameters.AddWithValue("@DrDncoundrlst", txtCountry.Text.ToString());
cmd.Parameters.AddWithValue("@DropDownListSwestate", txtState.Text.ToString());
cmd.Parameters.AddWithValue("@citytxtbox", txtCity.Text.ToString());
try
{
    cmd.Connection.Open();
    cmd.ExecuteNonQuery();
    cmd.Connection.Close();
    lblmsg.Text = "You already completed your registration process";
}
catch (SqlException ex)
{
    var errorMessage = "error in registration user";
    errorMessage += ex.Message;
    throw new Exception(errorMessage);
}
finally
{
    con.Close();
}

您还需要确保声明了以下using子句…

using System.Data;
using System.Data.SqlClient;

…并且txtCity是您实际称为文本框的内容，并且它不会通过private标识符隐藏此方法，或者实际上出现在不同的形式上，因为您得到的错误意味着变量在方法的范围之外，或者在您到达此方法之前其生命周期已过期。

下面是所有代码的作用。它不需要设置大量不需要声明参数的元数据，而是让SqlCommand为您完成所有艰苦的工作，并根据数据库列、传入的对象类型和参数名称确定类型。如果您最终允许传递无效数据，那么任何精心设计的元数据标记都无法使您避免出现错误。

同样，你真的想看看包装你的insertSql到一个存储过程，就像在Sql Server…

create procedure adduserinfo @UsrNme               nvarchar (50),
                             @fnbox                varchar (25),
                             @lnamebox             varchar (25),
                             @passtxtbx1           varchar (25),
                             @passtxtbx2           varchar (25),
                             @emailbox             varchar (25),
                             @DrDncoundrlst        varchar (25),
                             @DropDownListSwestate varchar (25),
                             @citytxtbox           varchar (25)
as begin
   INSERT INTO UserInfo 
     ( UID, 
       FN, 
       LN, 
       Password, 
       RePass, 
       Email, 
       Country,
       State, 
       City )
   VALUES
     ( @UsrNme, 
       @fnbox, 
       @lnamebox, 
       @passtxtbx1, 
       @passtxtbx2, 
       @emailbox, 
       @DrDncoundrlst, 
       @DropDownListSwestate, 
       @citytxtbox )
end
go

那么你的SqlCommand声明看起来像这样…

var command = new SqlCommand("adduserinfo", connection) 
{ 
    CommandType = CommandType.StoredProcedure; 
}

…至于其余部分，您可以按照我上面提供的其余代码进行操作。这或多或少是做这件事的适当方法。冒着听起来很挑剔的风险，考虑更多信息和一致格式的变量和参数名称。那些将来可能需要修改你代码的人会感谢你的。

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