C#字典类型转URL参数字符串

/// <summary>
/// 字典类型转URL参数字符串
/// </summary>
/// <param name="param"></param>
/// <returns></returns>
public static string DictionaryTostr(Dictionary<string, string> param)
{
StringBuilder builder = new StringBuilder();
foreach (var entry in param)
{
if (string.IsNullOrWhiteSpace(Convert.ToString(entry.Key)) || null == entry.Value)
{
continue;
}
builder.Append(Convert.ToString(entry.Key) + "=" + Convert.ToString(entry.Value) + "&");
}
return builder.ToString().Substring(0, builder.ToString().LastIndexOf("&")); ;
}