C# 在C语言中设置变量时遇到的问题#

我在变量

FaxPro

、

EmailPro

、

FaxStat

和

EmailStat

上遇到错误

while (reader.Read())
{
    string CustNo = reader["CUSTNO"].ToString();
    string Phone = reader["PHONE"].ToString();
    string Fax = reader["FAX"].ToString();
    string Email = reader["PRI_EMAIL"].ToString();
    string Type = reader["TYPE"].ToString();

    if (Type.Contains("H"))
    {
        if (Type.Contains("F"))
        {
            string FaxStat = "Y";
            string FaxPro = "PENDING";
        }
        else
        {
            string FaxStat = "N";
            string FaxPro = "NONE";
        }
        if (Type.Contains("E"))
        {
            string EmailStat = "Y";
            string EmailPro = "PENDING";
        }
        else
        {
            string EmailStat = "N";
            string EmailPro = "NONE";
        }
//outbox
// id, account, type, title, number, fax, email, faxpro, emailpro, faxstat, emailstat, filepath, datesent

        MySqlCommand mycommand = new MySqlCommand("INSERT INTO outbox (id, account, type, title, number, fax, email, faxpro, emailpro, faxstat, emailstat, filepath, datesent) VALUES('0','" + CustNo + "', 'CUSTOMER', 'test', '" + Phone + "', '" + Fax + "', '" + Email + "', '" + FaxPro + "', '" + EmailPro + "', '" + FaxStat + "', '" + EmailStat + "', 'test', NOW())", conn);
  mycommand.ExecuteNonQuery();

错误包括：

当前上下文C:…\Form2.cs中不存在名称“FaxPro”

---

。。。对于

EmailPro

、

FaxStat

、和

EmailStat

，等，在函数的开头声明字符串，使其始终具有作用域。目前，您正在

if/else

语句块中声明

FaxPro、EmailPro、FaxStat、EmailStat

，一旦该块结束，它们就超出范围

while (reader.Read())
{
    string CustNo = reader["CUSTNO"].ToString();
    string Phone = reader["PHONE"].ToString();
    string Fax = reader["FAX"].ToString();
    string Email = reader["PRI_EMAIL"].ToString();
    string Type = reader["TYPE"].ToString();

    if (Type.Contains("H"))
    {
        if (Type.Contains("F"))
        {
            string FaxStat = "Y";
            string FaxPro = "PENDING";
        }
        else
        {
            string FaxStat = "N";
            string FaxPro = "NONE";
        }
        if (Type.Contains("E"))
        {
            string EmailStat = "Y";
            string EmailPro = "PENDING";
        }
        else
        {
            string EmailStat = "N";
            string EmailPro = "NONE";
        }
//outbox
// id, account, type, title, number, fax, email, faxpro, emailpro, faxstat, emailstat, filepath, datesent

        MySqlCommand mycommand = new MySqlCommand("INSERT INTO outbox (id, account, type, title, number, fax, email, faxpro, emailpro, faxstat, emailstat, filepath, datesent) VALUES('0','" + CustNo + "', 'CUSTOMER', 'test', '" + Phone + "', '" + Fax + "', '" + Email + "', '" + FaxPro + "', '" + EmailPro + "', '" + FaxStat + "', '" + EmailStat + "', 'test', NOW())", conn);
  mycommand.ExecuteNonQuery();

通过在函数开始时声明一次，可以避免在

while

循环中多次声明它们

//small example
public void myFunc()
{
    string CustNo, Phone, Fax, Email, Type, FaxStat, FaxPro, EmailStat, EmailPro;

    //set up query and reader
    //...
    while(reader.read())
    {
         CustNo = reader["CUSTNO"].ToString();
         //etc.
    }
    //reader.close(); conn.close();
}

---

变量的声明超出范围。它们在if语句中声明。将声明移动到外部范围，如下所示：

while (reader.Read()) 
{ 
    string CustNo = reader["CUSTNO"].ToString(); 
    string Phone = reader["PHONE"].ToString(); 
    string Fax = reader["FAX"].ToString(); 
    string Email = reader["PRI_EMAIL"].ToString(); 
    string Type = reader["TYPE"].ToString(); 

    string FaxStat = string.Empty;
    string FaxPro = string.Empty;
    string EmailStat = string.Empty; 
    string EmailPro = string.Empty; 
    if (Type.Contains("H")) 
    { 
        if (Type.Contains("F")) 
        { 
            FaxStat = "Y"; 
            FaxPro = "PENDING"; 
        } 
        else 
        { 
            FaxStat = "N"; 
            FaxPro = "NONE"; 
        } 
        if (Type.Contains("E")) 
        { 
            EmailStat = "Y"; 
            EmailPro = "PENDING"; 
        } 
        else 
        { 
            EmailStat = "N"; 
            EmailPro = "NONE"; 
        } 
        //outbox 
        // id, account, type, title, number, fax, email, faxpro, emailpro, faxstat, emailstat, filepath, datesent 

        MySqlCommand mycommand = new MySqlCommand("INSERT INTO outbox (id, account, type, title, number, fax, email, faxpro, emailpro, faxstat, emailstat, filepath, datesent) VALUES('0','" + CustNo + "', 'CUSTOMER', 'test', '" + Phone + "', '" + Fax + "', '" + Email + "', '" + FaxPro + "', '" + EmailPro + "', '" + FaxStat + "', '" + EmailStat + "', 'test', NOW())", conn); 
        mycommand.ExecuteNonQuery(); 

---

您的变量超出范围-它们只存在于声明它们的{大括号}之间。请仔细阅读你的变量名应该小写。你不应该重新声明变量<代码>字符串传真状态=“Y”谢谢！我开始使用PHP。我想这会让你逃脱很多。但是，C#迫使我从一开始就学习编程。