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c#parenthesesnegation

c# negation operator open parenthesis expected

In C#, I'm writing code for negation operator like this, but it show syntax error, '(' expected

DataTable tmp = new DataTable();
var col = tmp.Columns;
if !(col.Contains("COL1") && col.Contains("COL2") && col.Contains("COL3"))
{
    //DO STH
}

If I change to this code the error disappear:

DataTable tmp = new DataTable();
var col = tmp.Columns;
if (!col.Contains("COL1") || !col.Contains("COL2") || !col.Contains("COL3"))
{
    //DO STH
}

Docs from MS seems too simple and I didn't find how to correct the first code.

So why the first code has syntax error, and how to fix it?

enter image description here

Solution

  • an if always starts with a ( so the code should be

    DataTable tmp = new DataTable();
var col = tmp.Columns;
if (!(col.Contains("COL1") && col.Contains("COL2") && col.Contains("COL3")))
{
    //DO STH
}