DataGridview的C＃彩色行

Question

我用这段代码改变了条件的行颜色，但代码不起作用！我不知道为什么，我有一个错误：

System.NullReferenceException类型的未处理的异常出现在DB（项目名称）的.exe

当我到达“ color = dataGridView1.Rows ....“

我该怎么办？

while (true) 
{ 
    color = dataGridView1[2, rowindex].Value.ToString(); 
    if (color == "IDLE") 
    { 
     dataGridView1.Rows[rowindex].DefaultCellStyle.BackColor = Color.Orange; 
    } 
    if (color == "ACTIVE") 
    { dataGridView1.Rows[rowindex].DefaultCellStyle.BackColor = Color.Green; } 
    if (color == "MAINTENANCE") 
    { dataGridView1.Rows[rowindex].DefaultCellStyle.BackColor = Color.Purple; } 
    if (color == "DISMISSED") 
    { dataGridView1.Rows[rowindex].DefaultCellStyle.BackColor = Color.Red; } 
    if (color == null) 
    { break; } 
    rowindex++; 
} 

Answer 1

foreach (DataGridViewRow row in dataGridView1.Rows) 
{ 
    if (row.Cells["color"] == "IDLE") 
    { 
     row.DefaultCellStyle.BackColor = Color.Orange; 
    } 
    else 
    if (row.Cells["color"] == "ACTIVE") 
    { 
     row.DefaultCellStyle.BackColor = Color.Green; 
    } 
    else 
    if (row.Cells["color"] == "MAINTENANCE") 
    { 
     row.DefaultCellStyle.BackColor = Color.Purple; 
    } 
    else 
    if (row.Cells["color"] == "DISMISSED") 
    { 
     row.DefaultCellStyle.BackColor = Color.Red; 
    } 
    //else 
    //{ 
    // break; //probably don't need this since the foreach will know when it's done looping through all the Rows 
    //} 
}