How to check if an XML node is null?

Question

I have a WS which has a method in which a list of Nodes with some data is inserted. I receive this data as Xmldocument, ride the knot Parameters reading the content inside it, after that I take the data and fill in the parameters of my Procedure to insert into the base.
However there is the possibility of case the data sent via WS is null, the node is not created, and when I try to read the error node.
In which way I can check if the node exists and if not insert NULL in the parameter of Procedure?

Follow the code I’m using to validate this, but it returns error

cmdMailingRetorno.Parameters.AddWithValue(
        "@DataHoraFim",
        Telefones[i]["DataHoraFim"].HasAttributes ?
            (DateTime?)null :
            Convert.ToDateTime(Telefones[i]["DataHoraFim"].InnerText)
);

Answer 1

Its validation is reversed if Telefones[i]["DataHoraFim"].HasAttributes for true, you are assigning (DateTime?)null as the value of your parameter. You can also check if Node also exists before checking if it has attributes, which also doesn’t make much sense as you are hoping to retrieve the value written inside the node.

Then you need to check if the node exists and if the InnerText is null or has some value.

cmdMailingRetorno.Parameters.AddWithValue(
      "@DataHoraFim",
      (Telefones[i]["DataHoraFim"] == null || !String.IsNullOrEmpty(["DataHoraFim"].InnerText))
      ? null 
      : Convert.ToDateTime(Telefones[i]["DataHoraFim"].InnerText)
);