C# for 循环：检查 DateTimePicker 是周末还是在数据库中

Question

我不是 IT 专业人士，所以下面的语法是错误的，但它显示了我想做什么。

我有两个 DateTimePicker：DateTimePicker1 和 DateTimePicker2（DateTimePicker1 < DateTimePicker2）。对于这两个 DateTimePicker 之间的任何日期，我想检查：

1. 如果是周末。
2. 如果它是数据库表中的日期。

有人可以帮我清理下面的代码吗？

谢谢！

public static bool isDateInDatabaseAppointmentTable(DateTime DateTimePicker.Value)  //How to write this statement. Check if the date is in database table
{

    OdbcConnection Cn = new OdbcConnection(GlobalVariables.DatabaseConnectionString);


    string select = "SELECT COUNT(*) from TableAppointment WHERE AppointmentDate = DataTimePicker.Value ";
    //How to write this SQL statement

    using (OdbcCommand cmd = new OdbcCommand(select, Cn))            
    {
        object obj = cmd.ExecuteScalar();

        int count = Convert.ToInt32(obj);

        if (count > 0)
        {
            return true;
        }
        else
        {
            return false;
        }                          

    }


}



for (DateTime dt = DateTimePicker1.Value to DateTimePicker2.Value) 
{
    bool isFound = GlobalMethod.isDateInDatabaseAppointmentTable(dt);

    if (dt == Satursday || dt == Sunday)
    {
    MessageBox.Show("It is weekend, you don't work today")
    //I will do something here, and I think I know how to do it. Just using messagebox to replace it.
    }  
    else if (isFound == true)   
    {
    MessageBox.Show("You have appointment today, and you don't work today")
    //I will do something here, and I think I know how to do it. Just using messagebox to replace it.
    }  
    else
    {
    //I will do something here.
    }


}

Note：此问题总结整理于: C# for loop: Checking if DateTimePicker is weekend or in database

Answer 1

根据您的代码，您需要注意一些问题。 首先，您需要使用形式参数而不是实际参数声明“isDateInDatabaseAppointmentTable”方法。 然后你就不能在 For 循环中使用 to 运算符。 最后，您可以使用 cheong00 所说的 DateTime.DayOfWeek 查看星期几。 以下是您可以参考的修改代码。

public static bool isDateInDatabaseAppointmentTable(DateTime dt)   
{  
   ....  
}  
  
private void button1_Click(object sender, EventArgs e)  
{  
    var startDate = dateTimePicker1.Value;  
    var endDate = dateTimePicker2.Value;  
    for (DateTime date = startDate; date <= endDate; date = date.AddDays(1))  
    {  
        bool isFound = isDateInDatabaseAppointmentTable(date);  
  
        if (date.DayOfWeek == DayOfWeek.Saturday || date.DayOfWeek == DayOfWeek.Sunday)  
        {  
            MessageBox.Show("It is weekend, you don't work today");  
        }  
        else if (isFound == true)  
        {  
            MessageBox.Show("You have appointment today, and you don't work today");  
  
        }  
        else  
        {  
        }  
    }  
}  

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