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Using null values in NamedReferences
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Can someone tell me how I can use null values in named references with an UltraCalcManager? I've created a formula editor which uses data from our database (using named references). However, sometimes the data contains null values. In that case, I want to assign a default value in the formula. But I can't seem to get it working. Below is some example code.

const string formula = "IF( ISNULL( [test] ), 100, [test] )";

var ultraCalcManager1 = new UltraCalcManager();
ultraCalcManager1.NamedReferences.Add("test", "75");

var result = ultraCalcManager1.Calculate(formula);

ultraCalcManager1.NamedReferences.Clear();
ultraCalcManager1.NamedReferences.Add("test", "null()");

result = ultraCalcManager1.Calculate(formula);

The first result is fine, but with the second result I get an error. I tried all sorts of different values for the null namedreference, like null without parentheses, or even without quotes. How can I accomplish this?

Thanks in advance!

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  • 469350
    Verified Answer
    Offline posted

    I tried this out and I am getting the same results. But the results I get are very strange. 

    If I tried this in the Form_Load event, I get the same results as you.

    If I create an UltraCalcManager and place it on the form and then use a TextBox control for the formula result, it works fine.

    Using a CalcManager that is on the form with the Calculate method does not work inside the Form_Load, but it works later on if I use a button_click event.

    So I think the problem is that the code you have here is trying to perform operations on the CalcManager synchonrously. You are expecting that when you add a new NamedReference to the NamedReferences collection that the NamedReference is immediately available for use in a formula. But this is not the case, by default. It works okay when your formula is '75' because that's a literal value and requires no extra calculation. But "null()" is a function. I also tried the same thing using "sum(5, 5)" and got the same results, so it's not just null that is a problem, it's any function. 

    Anyway, if I am right, then the solution is simply this:

    

                const string formula = "IF( ISNULL( [test] ), 100, [test] )";

                var ultraCalcManager1 = new UltraCalcManager();
                ultraCalcManager1.CalcFrequency = CalcFrequency.Synchronous;

                ultraCalcManager1.NamedReferences.Add("test", "75");

                var result = ultraCalcManager1.Calculate(formula);

                ultraCalcManager1.NamedReferences.Clear();
                ultraCalcManager1.NamedReferences.Add("test", "null()");

                result = ultraCalcManager1.Calculate(formula);    

    I tried this out and it works fine for me.

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