C#方法'ToString'的无重载采用1个参数

问题描述

这是我的错误所在:

foreach (var donneesDump in don)
{
    if (cap.Any(c => c.PMRQTOTM == donneesDump.PMRQTOTM))
    {
        if(!cap.Any(d => d.Libelle_TOT == donneesDump.Libelle_TOT))
        {
            cnn.Resultat.Add(new Resultat
            {
                NomTable = "CapitalisationActuelle",
                Groupe_D_alerte = donneesDump.Groupe_Alerte,
                NomChamp = "PMRQTOTM",
                TOTMPMRQ = donneesDump.PMRQTOTM,
                SiModifie = "Libelle TOT",
                LibelléTOTAvant = cap.Any(c => c.Libelle_TOT),
                LibelléTOTApres = donneesDump.Libelle_TOT,
                Remarque = "Ajoute"
            });
        }
    }
}

在线LibelléTOTAvant = cap.Any(c => c.Libelle_TOT)我有两个错误，最后都相同:

On line LibelléTOTAvant = cap.Any(c => c.Libelle_TOT)I have two errors, which are finally the same:

我试图做一个ToString()方法来解决这个问题，像这样:

I have tried to do a ToString() Method to solve the problem, like this:

LibelléTOTAvant = ToString(cap.Any(c => c.Libelle_TOT)),

然后出现错误:

这不是我第一次遇到这种错误，但是我仍然找不到解决方法.

It isn't the first time I have this kind of error, but I still don't find how solve this..

先谢谢了.问候.

这是我的位置.

foreach (var donneesDUMP in don)
{
    if (cap.Any(c => c.PMRQTOTM == donneesDUMP.PMRQTOTM))
    {
        if(!cap.Any(c => c.Libelle_TOT == donneesDUMP.Libelle_TOT))
        {
            cnn.Resultat.Add(new Resultat
            {
                NomTable = "CapitalisationActuelle",
                Groupe_D_alerte = donneesDUMP.Groupe_Alerte,
                NomChamp = "PMRQTOTM",
                TOTMPMRQ = donneesDUMP.PMRQTOTM,
                SiModifie = "Libelle TOT",
                LibelléTOTAvant = cap.Select(c => c.Libelle_TOT).FirstOrDefault(),
                //LibelléTOTAvant = cap.Any(c => !string.IsNullOrEmpty(c.Libelle_TOT))
                //? cap.Select(x => x.Libelle_TOT).First(l => !string.IsNullOrEmpty(l))
                //: " ",
                LibelléTOTApres = donneesDUMP.Libelle_TOT,
                Remarque = "Modifie"
            });

        }
    }
}

两者

LibelléTOTAvant = cap.Select(c => c.Libelle_TOT).FirstOrDefault(),

和

LibelléTOTAvant = cap.Any(c => !string.IsNullOrEmpty(c.Libelle_TOT))
                        ? cap.Select(x => x.Libelle_TOT).First(l => !string.IsNullOrEmpty(l))
                        : " ",

有效.但是每次我遇到一个问题时，可能都是.First()和.FirstOrDefault().它总是写第一个Libelle_TOT，而不是好的.

works. But each time I have one problem, probably with .First() and .FirstOrDefault().It always write the first Libelle_TOT, not the good one.

推荐答案

我相信Libelle_TOT是一个字符串(来自Cannot implicitly convert type 'string' to 'bool'.错误消息)

I believe Libelle_TOT is a string (from the Cannot implicitly convert type 'string' to 'bool'. error message)

cap.Any(c => c.Libelle_TOT)在这种情况下没有意义，因为Any应该以Func<T, bool>作为参数(返回布尔值)，并且您传递Func<T, string>.

cap.Any(c => c.Libelle_TOT) doesn't make sense in this case, as Any should have a Func<T, bool> as argument (something returning a bool) and you pass a Func<T, string>.

所以你应该做

cap.Any(c => !string.IsNullOrEmpty(c.Libelle_TOT))

例如，

或其他任何需要返回布尔值的东西.

for example, or anything else needed which would return a bool.

，如果LibelléTOTAvant是字符串

cap.Any(c => !string.IsNullOrEmpty(c.Libelle_TOT))
   ? <something which is a string>
   : <something else which is a string>

编辑

例如

cap.Any(c => !string.IsNullOrEmpty(c.Libelle_TOT))
   ? cap.Select(x => x.Libelle_TOT).First(l => !string.IsNullOrEmpty(l))
   : 'No Label'

或者在这种情况下，您可以

or in this case, you could do

   cap.Select(x => x.Libelle_TOT).FirstOrDefault(l => !string.IsNullOrEmpty(l)) ?? 'No Label'

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