将头添加到不存在的文件然后追加

Question

随着社区的一些以前的反馈，我已经实现了一个函数，用于检查文件是否存在，如果不存在，那么它会写入头文件和数据，但如果它存在它只能附加到它。那么这就是它应该做的，但它所做的只是写入没有标题的数据。就好像它跳出第一个条件，然后进入下一个条件。我哪里错了？

private void button6_Click_2(object sender, EventArgs e) 
    { 

     int count_row = dataGridView1.RowCount; 
     int count_cell = dataGridView1.Rows[0].Cells.Count; 
     string path = "C:\\Users\\jdavis\\Desktop\\" + comboBox5.Text + ".csv"; 
     string rxHeader = "Code" + "," + "Description" + "," + "NDC" + "," + "Supplier Code" 
     + "," + "Supplier Description" + "," + "Pack Size" + "," + "UOM"; 


     MessageBox.Show("Please wait while " + comboBox5.Text + " table is being exported.."); 

     for (int row_index = 0; row_index <= count_row - 2; row_index++) 
     { 

      for (int cell_index = 1; cell_index <= count_cell - 1; cell_index++) 
      { 
       textBox8.Text = textBox8.Text + dataGridView1.Rows[row_index].Cells[cell_index].Value.ToString() + ","; 

      } 
      textBox8.Text = textBox8.Text + "\r\n"; 

      if (!File.Exists(path)) 
      { 
       System.IO.File.WriteAllText(path, rxHeader); 
       System.IO.File.WriteAllText(path, textBox8.Text); 
      } 
      else 
      {  
       System.IO.File.AppendAllText(path, textBox8.Text); 
       MessageBox.Show("Export of " + comboBox5.Text + " table is complete!"); 
       textBox8.Clear(); 
      } 
     } 
    } 

Answer 1

的问题是，File.WriteAllText覆盖文件的内容，那么你的第二File.WriteAllText覆盖头。您可以更改您的代码，如下所示：

 if (!File.Exists(path)) 
     { 
      System.IO.File.WriteAllText(path, rxHeader + textBox8.Text); 
     } 
     else 
     {  
      System.IO.File.AppendAllText(path, textBox8.Text); 
      MessageBox.Show("Export of " + comboBox5.Text + " table is complete!"); 
      textBox8.Clear(); 
     }