title: System.Data.SqlClient.SqlParameterCollection does not contain a definition for 'AddWithvalue'
body: <pre><code>    public static DataTable SqlDataTable(string sql, IDictionary&lt;string, object&gt; values)
      {
          using (SqlConnection conn = new SqlConnection(GetConnectionString))
          using (SqlCommand cmd = new SqlCommand(sql, conn))
          {
              conn.Open();
  
              foreach (var item in values)
              {
                  cmd.Parameters.AddWithvalue("@" + item.Key, item.Value);  // error
              }
            .......
            ........
  </code></pre>
  
  <blockquote>
    <p>Error 4   'System.Data.SqlClient.SqlParameterCollection' does not
    contain a definition for 'AddWithvalue' and no extension method
    'AddWithvalue' accepting a first argument of type
    'System.Data.SqlClient.SqlParameterCollection' could be found (are you
    missing a using directive or an assembly reference?)</p>
  </blockquote>
  
  <p>Why I get this error ?</p>