Question

大家好我写了下面的代码，我正在做的是我想使用Switch案例来存在我的dictionary，但我收到错误

Can not implicitly convert string to bool

我的代码如下

List<string> lst = new List<string>();
lst.Add("Delete");
lst.Add("Reports");
lst.Add("Customer");

Dictionary<int, string> d = new Dictionary<int, string>();
d.Add(1, "Delete");
d.Add(2, "Reports");

    foreach (string i in lst)
    {
        if (d.ContainsValue(i))
        {
            switch (d.ContainsValue(i))
            {
                case "Delete": // Here i would like to compare my value from dictionary
                    //link1.NavigateUrl = "Reports.aspx";
                    HyperLink1.NavigateUrl = "Delete.aspx";
                    break;
            }


        }
        else
        {
            HyperLink2.Attributes["OnClick"] = "alert('Not a Valid User to Perform this operation'); return false";
        }
    }

Answer 1

d.ContainsValue(i)

返回布尔值。当你这样做时：

case "Delete"

您尝试将bool与字符串进行比较，因此失败。你需要这样做：

if (d.ContainsValue(i))
{
    switch (i)
    {
        case "Delete": // Here i would like to compare my value from dictionary
            //link1.NavigateUrl = "Reports.aspx";
            HyperLink1.NavigateUrl = "Delete.aspx";
            break;
    }
}

Answer 2

请尝试以下操作：switch (d[i])

使用TryGetValue

可能更有效率

Answer 3

if中的switch会返回一个布尔值，而case表示它必须是string

 switch (d.ContainsValue(i))
            {
                case "Delete": // Here i would like to compare my value from dictionary
                    //link1.NavigateUrl = "Reports.aspx";
                    HyperLink1.NavigateUrl = "Delete.aspx";
                    break;
            }

试试这个

switch (d[i])
                {
                    case "Delete": // Here i would like to compare my value from dictionary
                        //link1.NavigateUrl = "Reports.aspx";
                        HyperLink1.NavigateUrl = "Delete.aspx";
                        break;
                }

Answer 4

你可以做这样的事情，避免一起切换：

var lst = new List<string>();
lst.Add("Delete");
lst.Add("Reports");
lst.Add("Customer");

Dictionary<int, string> d = new Dictionary<int, string>();
d.Add(1, "Delete");
d.Add(2, "Reports");

var hyperlinkMap = new Dictionary<string, string>()
{
    { "Delete", "Delete.aspx"},
    { "Reports", "Reports.aspx"}
};

foreach (var i in lst)
{
    if(d.ContainsValue(i))
    {
        HyperLink1.NavigateUrl = hyperlinkMap[i];
    }
    else
    {
        HyperLink2.Attributes["OnClick"] = "alert('Not a Valid User to Perform this operation'); return false";
    }
}

案例陈述与字典

4 个答案: