计算最小值和最大值C＃

Question

我试图从datagridview中计算最大值。 这里是我的全部代码：

namespace WindowsFormsApplication2 
{ 
public partial class Form1 : Form 
{ 
    public Form1() 
    { 
     InitializeComponent(); 
    } 

    public class HRData 
    { 
     public int? HeartRate 
     { 
      get; 
      set; 
     } 
     public int? Speed 
     { 
      get; 
      set; 
     } 
     public int? Power 
     { 
      get; 
      set; 
     } 
     public int? Altitude 
     { 
      get; 
      set; 
     } 

     public override string ToString() 
     { 
      return String.Format("Heart rate={0}, Speed={1}, Power={2}, Altitude={3}", HeartRate, Speed, Power, Altitude); 
     } 
    } 





    public static class HRDataReader 
    { 
     static private int? ConvertValue(string[] values, int index) 
     { 
      if (index >= values.Length) 
       return null; 
      int value; 
      if (int.TryParse(values[index], out value)) 
       return value; 
      return null; 
     } 

     static public IList<HRData> Read(string fileName) 
     { 
      if (string.IsNullOrEmpty(fileName)) 
       throw new ArgumentNullException("fileName"); 
      using (StreamReader sr = new StreamReader(fileName)) 
      { 
       string line; 

       // First: Skip to the correct section. 
       while ((line = sr.ReadLine()) != null) 
        if (line == "[HRData]") 
         break; 

       // Now: Read the HRData 
       List<HRData> data = new List<HRData>(); 
       while ((line = sr.ReadLine()) != null) 
       { 
        if (line.StartsWith("[") && line.EndsWith("]")) 
         break; 
        line = line.Trim().Replace("\t", " "); // Remove all tabs. 
        while (line.Contains(" ")) // Remove all duplicate spaces. 
         line = line.Replace(" ", " "); 
        string[] values = line.Split(' '); // Split the line up. 
        data.Add(new HRData 
        { 
         HeartRate = ConvertValue(values, 0), 
         Speed = ConvertValue(values, 1), 
         Power = ConvertValue(values, 2), 
         Altitude = ConvertValue(values, 3) 
        }); 
       } 
       return data; 
      } 
     } 
    } 


    private void Form1_Load(object sender, EventArgs e) 
    { 

    } 

    private void button1_Click_1(object sender, EventArgs e) 
    { 
     if (openFileDialog1.ShowDialog() == DialogResult.OK) 
     { 
      dataGridView1.Rows.Clear(); 
      dataGridView1.Columns.Clear(); 

      IList<HRData> data = HRDataReader.Read(openFileDialog1.FileName); 

      dataGridView1.Columns.Add(new DataGridViewTextBoxColumn { Name = "HeartRate", HeaderText = "Heart rate", DataPropertyName = "HeartRate" }); 
      dataGridView1.Columns.Add(new DataGridViewTextBoxColumn { Name = "Speed", HeaderText = "Speed", DataPropertyName = "Speed" }); 
      dataGridView1.Columns.Add(new DataGridViewTextBoxColumn { Name = "Power", HeaderText = "Power", DataPropertyName = "Power" }); 
      dataGridView1.Columns.Add(new DataGridViewTextBoxColumn { Name = "Altitude", HeaderText = "Altitude", DataPropertyName = "Altitude" }); 

      dataGridView1.DataSource = data; 

      int maxSpeed = Speed.Max(); 
      maxSpeed = maxSpeed/10; 
      string MaxSpeed = Convert.ToString(maxSpeed); 
      textBox1.Text = MaxSpeed;  
     } 
    } 
} 

}

我收到一条错误 '廉政MAXSPEED = Speed.Max（）;'

该错误消息说，

“名称‘速度’并没有在当前的背景下存在”我不知道我应该把什么样的价值在那里代表我的一列。希望有人能够帮助我解决这个问题。谢谢。

Answer 1

速度不是一个类或一个对象，所以它不知道它是什么。你必须使用一个函数和一个集合：

int maxSpeed = data.Max(x => x.Speed.Value); 

See the documentation on list max for more information and sample code.

Answer 2

你或许应该使用Math.Max Method (Double, Double)和Math.Min Method (Double, Double)在标准的.NET C＃库包括

Answer 3

像这样的事情可能？

int minAccountLevel = int.MaxValue; 
int maxAccountLevel = int.MinValue; 
foreach (DataGridViewRow dr in table.Rows) 
{ 
    int accountLevel = dr.Cells["Speed"]; 
    minAccountLevel = Math.Min(minAccountLevel, accountLevel); 
    maxAccountLevel = Math.Max(maxAccountLevel, accountLevel); 
} 

来源：https://stackoverflow.com/a/2442717/1908499