虛擬DataGridView與多種顏色的行導致CellValueNeeded比賽

Question

我遇到了一個奇怪的問題，我第一次嘗試在虛擬DataGridView。網格顯示來自DataTable的數據，行根據狀態列的值進行顏色編碼。我使用事件RowPostPaint根據其狀態值設置每行的顏色。

只要網格中的行在所有列中具有相同的顏色，此功能就很有用。但是，當我在每行中引入多種顏色時，網格變得瘋狂並持續觸發CellValueNeeded事件，並且CPU使用率高達100％。只要多色的行滾動出來，問題就會消失。

DataGridView在常規模式下沒有問題。但是，我真的很想使用虛擬DataGridView來實現最佳性能。有沒有人知道這個問題以及如何避免它？

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Windows.Forms; 
using System.Diagnostics; 

namespace VirtualDGV 
{ 
    public partial class Form1 : Form 
    { 
     protected Color greenColor = Color.FromArgb(200, 240, 140); 
     protected Color redColor = Color.FromArgb(255, 100, 50); 
     protected Color cyanColor = Color.FromArgb(175, 255, 225); 
     protected Color pinkColor = Color.FromArgb(255, 200, 150); 

     private DataTable data = null; 

     public Form1() 
     { 
      InitializeComponent(); 

      LoadData2(); 

      dgv.VirtualMode = true; 

      dgv.CellValueNeeded += new DataGridViewCellValueEventHandler(dgv_CellValueNeeded); 
      dgv.RowPostPaint += new DataGridViewRowPostPaintEventHandler(dgv_RowPostPaint); 
     } 

     private void CreateDataTable() 
     { 
      if (data != null) 
      { 
       data.Clear(); 
       data.Dispose(); 
       data = null; 
      } 

      data = new DataTable(); 
      List<DataColumn> columns = new List<DataColumn>(); 
      columns.Add(new DataColumn("A", typeof(string))); 
      columns.Add(new DataColumn("B", typeof(string))); 
      columns.Add(new DataColumn("C", typeof(DateTime))); 
      columns.Add(new DataColumn("D", typeof(DateTime))); 
      columns.Add(new DataColumn("E", typeof(string))); 
      columns.Add(new DataColumn("F", typeof(double))); 
      columns.Add(new DataColumn("G", typeof(double))); 
      columns.Add(new DataColumn("H", typeof(string))); 
      columns.Add(new DataColumn("I", typeof(string))); 
      columns.Add(new DataColumn("J", typeof(int))); 
      columns.Add(new DataColumn("Status", typeof(int))); 


      data.Columns.AddRange(columns.ToArray()); 
     } 


     private void LoadData1() 
     { 
      CreateDataTable(); 

      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 2); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 1); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 5); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 5); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 5); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 

      dgv.RowCount = data.Rows.Count; 
     } 

     private void LoadData2() 
     { 
      CreateDataTable(); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 9); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 
      data.Rows.Add("Abcdefghijklmnopqrstuvwxyz", "XYZ", DateTime.Now, DateTime.Now, "ZZZ", 110, 110, "", "", 250, 0); 

      dgv.RowCount = data.Rows.Count; 
     } 


     protected void SetRowColor(DataGridViewRow row, int status, int dateColumn, int amountColumn) 
     { 
      switch (status) 
      { 
       case 10: 
        for (int i = 1; i < row.Cells.Count; i++) 
         row.Cells[i].Style.BackColor = greenColor; 

        row.Cells[dateColumn].Style.BackColor = Color.FromArgb(255, 170, 130); 
        break; 

       case 11: 
        row.Cells[dateColumn].Style.BackColor = Color.FromArgb(255, 170, 130); 
        row.Cells[amountColumn].Style.BackColor = greenColor; 
        break; 

       case 1: 
        for (int i = 1; i < row.Cells.Count; i++) 
         row.Cells[i].Style.BackColor = greenColor; 
        break; 

       case 2: 
        for (int i = 1; i < row.Cells.Count; i++) 
         row.Cells[i].Style.BackColor = greenColor; 

        row.Cells[amountColumn].Style.BackColor = pinkColor; 
        break; 

       case 3: 
        for (int i = 1; i < row.Cells.Count; i++) 
         row.Cells[i].Style.BackColor = greenColor; 

        row.Cells[dateColumn].Style.BackColor = Color.FromArgb(255, 170, 130); 
        break; 

       case 4: 
        row.Cells[dateColumn].Style.BackColor = Color.FromArgb(255, 170, 130); 
        row.Cells[amountColumn].Style.BackColor = Color.FromArgb(255, 200, 150); 
        break; 

       case 5: 
        for (int i = 1; i < row.Cells.Count; i++) 
         row.Cells[i].Style.BackColor = redColor; 
        break; 

       case 6: 
        for (int i = 1; i < row.Cells.Count; i++) 
         row.Cells[i].Style.BackColor = cyanColor; 
        break; 

       case 7: 
        row.Cells[amountColumn].Style.BackColor = greenColor; 
        break; 

       case 8: 
        for (int i = 1; i < row.Cells.Count; i++) 
         row.Cells[i].Style.BackColor = cyanColor; 
        break; 

       case 9: 
        for (int i = 1; i < row.Cells.Count; i++) 
         row.Cells[i].Style.BackColor = greenColor; 

        row.Cells[dateColumn].Style.BackColor = redColor; 
        row.Cells[amountColumn].Style.BackColor = redColor; 
        break; 

      } 
     } 


     private void dgv_CellValueNeeded(object sender, DataGridViewCellValueEventArgs e) 
     { 
      //Debug.WriteLine(e.RowIndex + ", " + e.ColumnIndex); 

      e.Value = data.Rows[e.RowIndex][e.ColumnIndex]; 
     } 

     private void dgv_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e) 
     { 
      SetRowColor(dgv.Rows[e.RowIndex], (int)data.Rows[e.RowIndex]["Status"], 4, 7); 
     } 
    } 
} 

Answer 1

手柄CellFormatting事件，而不是RowPostPaint這樣的：

private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e) 
{ 
    if (e.RowIndex == 1 && e.ColumnIndex == 2) 
    { 
     e.CellStyle.ForeColor = Color.Red; 
    } 
} 

使用專門的CellStyle財產，不碰dgv[col, row].Style屬性，因爲將再次觸發事件。