MATLAB: How to add constant line in appdesigner

appdesignerline plot

I want to add a constant line in the plot axes in appdesigner. I tried the command plot(app.UIAxes,xline(app.DCValueDropDown.Value)) where the drop down values are values from (10 to 20). But it isnt working. Any ideas please?

Best Answer

Data type of dropdown.Value is a character, so you need to covert it to number.
The following will work. Please replace "plot" command depending on your data.
function startupFcn(app)
    plot(app.UIAxes, 1:20, 1:20)
    app.xl = xline(app.UIAxes, str2double(app.DCValueDropDown.Value));
end
function DCValueDropDownValueChanged(app, event)
    value = app.DCValueDropDown.Value;
    % Change xline value
    app.xl.Value = str2double(value);
end
Below is a preview.
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