需要名稱空間

using System.IO;

介面:

記得新增openFileDialog

注意名字,改成跟程式碼裡的對應

寫檔案按鈕程式碼:

  private void button2_Click(object sender, EventArgs e)
        {
            int i = 0;
            StreamWriter aFile = null;
            aFile = File.CreateText("aFile .csv");
          
         
           
         //aFile.WriteLine(i.ToString() + "," + (i + 1).ToString() + "," + (i + 2));
          aFile.WriteLine("\"" + i.ToString() + "," + (i + 1).ToString() + "," + (i + 2)+"\"");
         //aFile.WriteLine("\""+i.ToString() + "," + (i + 1).ToString() +"\""+ "," + (i + 2));
            aFile.Close();
                aFile.Dispose();
                MessageBox.Show("end!");
        }
 

注意逗號分隔符的用法,逗號分隔符把內容分成幾個單元格.

如果要在同一個單元格中寫入逗號,則要在該單元格內容前後加上雙引號加上,3種情況產生的格式如下:

aFile.WriteLine(i.ToString() + "," + (i + 1).ToString() + "," + (i + 2));

aFile.WriteLine("\"" + i.ToString() + "," + (i + 1).ToString() + "," + (i + 2)+"\"");

aFile.WriteLine("\""+i.ToString() + "," + (i + 1).ToString() +"\""+ "," + (i + 2));
 

讀檔案按鈕按鈕:

  private void button1_Click(object sender, EventArgs e)
        {
            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                string str = null;

                FileStream fs = new FileStream(openFileDialog.FileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
                StreamReader reader = new StreamReader(fs, System.Text.Encoding.UTF8);
                while ((str = reader.ReadLine()) != null)
                {


                    // split the string
                    //MessageBox.Show(str);
                    string[] strs = str.Split(',');
                    string show_str = "";
                    for(int i=0;i<strs.Length;i++)
                    {
                        if (i == strs.Length-1)
                        {
                            show_str += strs[i].ToString();
                        }
                        else
                        {
                            show_str += strs[i].ToString() + ",";
                        }
                    }
                    this.label1.Text = show_str;
                }
                reader.Close();
            }
        }
 

上面三種寫入方式讀出的字串對應如下：

對應讀出的字串:

str=0,1,2

即strs[0]=0

strs[1]=1

strs[2]=2

對應的字串:

str="0,1,2",

即strs[0]="0

strs[1]=1

strs[2]=2"

對應的字串:

str="0,1",2,

即strs[0]="0

 strs[1]=1"

strs[2]=2