How to pass "select" parameters to R script?


I am trying to insert a parameter as “select” type and pass the parameter to Rscript. But in my local galaxy, the parameter cannot be displayed at all. Are there any simple examples for setting “select” parameter?

Here is my code:

<command detect_errors="exit_code">
        Rscript '${__tool_directory__}/correlationMatrix.R'
            --f ='$expressionData'
            --c ='$correlationMatrix'
            --m ='$method'                     
    <param name="expressionData" type="data" format="tabular" label="expression data in tabular txt file format.Rows are samples and columns are genes"/>            
    <param name="method" type="select"  label="select one method"/>
            <option value="pearson">Pearson </option>
            <option value="spearman">Spearman rank </option>
            <option value="kendall">kendall rank </option>

    <data format="txt" name="correlationMatrix" label="Correlation matrix on ${on_string}" />