C＃| Convert.ToInt64(String，IFormatProvider)方法

此方法用于使用指定的区域性特定格式信息将数字的指定字符串表示形式转换为等效的64位带符号整数。

句法：

public static long ToInt64 (string value, IFormatProvider provider);

参数：

• value：它是一个包含要转换的数字的字符串。
• provider：提供者：提供特定于区域性的格式信息的对象。

返回值：该方法返回一个十进制数字，该数字等于value中的数字；如果value为null ，则返回0(零)。

例外情况：

• FormatException：如果该值不包含一个可选的符号，后跟一个数字序列(0到9)。
• OverFlowException：如果该值表示一个小于MinValue或大于MaxValue的数字。

下面的程序说明了Convert.ToInt64(String，IFormatProvider)方法的用法：

范例1：

// C# program to demonstrate the
// Convert.ToInt64() Method
using System;
using System.Globalization;
  
class GFG {
  
// Main Method
public static void Main()
{
    try {
  
        // creating object of CultureInfo
        CultureInfo cultures = new CultureInfo("en-US");
  
        // declaring and initializing String array
        string[] values = {"12345", "+12345",
                                   "-12345"};
  
        // calling get() Method
        Console.Write("Converted long value"
                    + " from a specified string ");
  
        for (int j = 0; j < values.Length; j++) 
        {
            get(values[j], cultures);
        }
    }
  
    catch (FormatException e)
    {
        Console.WriteLine("\n");
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }
  
    catch (OverflowException e)
    {
        Console.WriteLine("\n");
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }
}
  
// Defining get() method
public static void get(string s,
           CultureInfo cultures)
{
  
    // converting string to specified long
    long val = Convert.ToInt64(s, cultures);
  
    // display the converted long value
    Console.Write(" {0}, ", val);
}
}

输出：

Converted long value from a specified string  12345,  12345,  -12345,

示例2：对于FormatException

// C# program to demonstrate the
// Convert.ToInt64() Method
using System;
using System.Globalization;
  
class GFG {
  
// Main Method
public static void Main()
{
      
    try {
  
        // creating object of CultureInfo
        CultureInfo cultures = new CultureInfo("en-US");
  
        // declaring and initializing String array
        string[] values = {"12345", "+12345",
                                   "-12345"};
  
        // calling get() Method
        Console.Write("Converted long value"
                    + " of specified strings: ");
  
        for (int j = 0; j < values.Length; j++) 
        {
            get(values[j], cultures);
        }
  
        Console.WriteLine("\n");
        string s = "123 456, 789";
  
        Console.WriteLine("format of s is invalid ");
  
        // converting string to specified char
        long val = Convert.ToInt64(s, cultures);
  
        // display the converted char value
        Console.Write(" {0}, ", val);
    }
  
    catch (FormatException e)
    {
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }
  
    catch (OverflowException e) 
    {
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }
}
  
// Defining get() method
public static void get(string s,
           CultureInfo cultures)
{
  
    // converting string to
    // specified long value
    long val = Convert.ToInt64(s, cultures);
  
    // display the converted
    // decimal value
    Console.Write(" {0}, ", val);
}
}

输出：

Converted long value of specified strings:  12345,  12345,  -12345, 

format of s is invalid 
Exception Thrown: System.FormatException

示例3：对于OverflowException

// C# program to demonstrate the
// Convert.ToInt64() Method
using System;
using System.Globalization;
  
class GFG {
  
// Main Method
public static void Main()
{
  
    try {
  
        // creating object of CultureInfo
        CultureInfo cultures = new CultureInfo("en-US");
  
        // declaring and initializing String array
        string[] values = {"12345", "+12345",
                                   "-12345"};
  
        // calling get() Method
        Console.Write("Converted long value "
                 + "of specified strings: ");
  
        for (int j = 0; j < values.Length; j++)
        {
            get(values[j], cultures);
        }
  
        Console.WriteLine("\n");
        string s = "-7922816251426433759354395033500000";
  
        Console.WriteLine("s is less than the MinValue");
  
        // converting string to specified long
        long val = Convert.ToInt64(s, cultures);
  
        // display the converted char value
        Console.Write(" {0}, ", val);
    }
  
    catch (FormatException e)
    {
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }
  
    catch (OverflowException e) 
    {
        Console.Write("Exception Thrown: ");
        Console.Write("{0}", e.GetType(), e.Message);
    }
}
  
// Defining get() method
public static void get(string s,
           CultureInfo cultures)
{
  
    // converting string to
    // specified long value
    long val = Convert.ToInt64(s, cultures);
  
    // display the converted long value
    Console.Write(" {0}, ", val);
}
}

输出：

Converted long value of specified strings:  12345,  12345,  -12345, 

s is less than the MinValue
Exception Thrown: System.OverflowException

参考：

• https://docs.microsoft.com/zh-cn/dotnet/api/system.convert.toint64?view=netframework-4.7.2#System_Convert_ToInt64_System_String_System_IFormatProvider_