C#

Call a JavaScript Function Returning a Boolean

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Demonstrates how to call a JavaScript function that returns a boolean. C#

bool success = false;

// This is the JavaScript function we'll call:

// function isEven(number) {
//     return number % 2 === 0;
// }

Chilkat.StringBuilder sbScript = new Chilkat.StringBuilder();
sbScript.Append("function isEven(number) { return number % 2 === 0; }");

Chilkat.Js js = new Chilkat.Js();

Chilkat.JsonObject result = new Chilkat.JsonObject();
result.EmitCompact = false;

// Call Eval to add the function to the context's global object
success = js.Eval(sbScript,result);
if (success == false) {
    // Examine the result for an exception.
    Debug.WriteLine(result.Emit());

    // Also examine the LastErrorText.
    Debug.WriteLine(js.LastErrorText);
    return;
}

// ------------------------------------------------------------------------------
// Call the function isEven(8)

Chilkat.JsonObject funcCall = new Chilkat.JsonObject();

// Create JSON specifying the function name and arguments

// {
//   "name": "isEven",
//   "args": [ 8 ]
// }

funcCall.UpdateString("name","isEven");
funcCall.UpdateInt("args[0]",8);

success = js.CallFunction(funcCall,result);
if (success == false) {
    // Examine the result for an exception.
    Debug.WriteLine(result.Emit());

    // Also examine the LastErrorText.
    Debug.WriteLine(js.LastErrorText);
    return;
}

Debug.WriteLine(result.Emit());

// Output:
// {
//   "type": "bool",
//   "value": true
// }

bool retval = result.BoolOf("value");
Debug.WriteLine(Convert.ToString(retval));

// Output:
// true