您的问题是:listDonnees [cpt]是一个List，您只需要获取List>的内部列表.如果您想知道内部列表是否包含 #FFFFFF ，则需要使用.Contains()

Your problem is that: listDonnees[cpt] is a List, you just take the inner list of you List>. If you want to know if the inner List contains the #FFFFFF you need to use .Contains()

listDonnees[cpt].Contains("#FFFFFF")

或者您对-循环使用第二个(嵌套的)循环来检查每个字符串. 顺便说一句:您可以使用以下方法更轻松地进行检查:

Or you use a second (nested) for - loop to check every string. By the way: You can check easier by using this:

colore = listDonnees[cpt].Any(s =>new List<String>() {"#FFFFFF", "#FFD700", "#FF6347"}.Contains(s));

所以对您来说尤其是问题:

So for you problem in particular:

int nbItems = listDonnees.Count ;
var hashCodes = new List<String>() {"#FFFFFF", "#FFD700", "#FF6347"};

for(int cpt = 0; cpt < nbItems; cpt++)
{
    string colorcode = string.Empty;
    if(cpt + 1 < nbItems)
    {
       colorcode = listDonnees[cpt].FirstOrDefault(s => hashCodes.Contains(s));
    }
    if(colorcode != string.Empty)
    {
       <td style="background-color:@colorcode">colorcode</td>
       //cpt++; See below!    
     }
     else
     {
         var str = String.Join(",", listDonnees[cpt]);
         <td>str</td>
     }
     // I Think your cpt++; needs to be here:
     cpt++;
}

我不认识您的模型，所以您可能需要更改@ViewBag的访问权限.

I don't know you Model, so you might habe to change your @ViewBag accessing a bit.