Wrong Type of Argument

Question

I have next function
GetData("CasCadingDropDownList.spGETCOUNTRIES", "cur_countries",
new OracleParameter ("pContinentId", ddlContinents.SelectedValue));
pcontinentid is number


Defining GetData:
private DataSet GetData(string spName, string crsName, OracleParameter spParameter)
I add in source
cmd.Parameters.Add(spParameter).Direction = ParameterDirection.Input;


But my type of spParameter is wrong! How can i change this?