メソッドのインテリセンスを見てください。それは次のとおりです。
//
// Summary:
// Returns a new string in which all the characters in the current instance,
// beginning at a specified position and continuing through the last position,
// have been deleted.
//
// Parameters:
// startIndex:
// The zero-based position to begin deleting characters.
//
// Returns:
// A new string that is equivalent to this string except for the removed characters.
//
// Exceptions:
// System.ArgumentOutOfRangeException:
// startIndex is less than zero.-or- startIndex specifies a position that is
// not within this string.
public string Remove(int startIndex);
それはそれが言うことをします。それはあなたが望む方法ではありません。あなたが望むものは:
string s = "hello".Replace("e","");