1..NET默认情况下应全局匹配。
1.我不知道对/g的支持，因为这是一个Perl主义，所以删除它，和领先的/，.NET正试图从字面上匹配它们。

正则表达式在这里可能是矫枉过正，如果属性或值包含特殊字符，或者将作为正则表达式本身进行计算的字符，甚至可能会引入问题。
一个简单的替换应该工作：

Dictionary<string, string> properties = new Dictionary<string, string>()
{
    { "property1", @"E:\" },
    { "property2", @"$(property1)\Temp"},
    { "property3", @"$(property2)\AnotherSubFolder"}
};

Dictionary<string, string> newproperties = new Dictionary<string, string>();

// Iterate key value pairs in properties dictionary, evaluate values
foreach ( KeyValuePair<string,string> kvp in properties ) {
  string value = kvp.Value;
  // Execute replacements on value until no replacements are found
  // (Replacement of $(property2) will result in value containing $(property1), must be evaluated again)
  bool complete = false;
  while (!complete) {
    complete = true;
    // Look for each replacement token in dictionary value, execute replacement if found
    foreach ( string key in properties.Keys ) {
      string token = "$(" + key + ")";
      if ( value.Contains( token ) ) {
        value = value.Replace( "$(" + key + ")", properties[key] );
        complete = false;
      }
    }
  }
  newproperties[kvp.Key] = value;
}

properties = newproperties;