How to convert Dictionary<string, object> to Dictionary<string, string> in c#

Question

I have below code in C#

Dictionary<string, object> dObject = new Dictionary<string, object>(); 

I want to convert dObject to Dictionary<string, string>. How can I do this?

Answer 1

Use the ToDictionary method:

Dictionary<string, string> dString = dObject.ToDictionary(k => k.Key, k => k.Value.ToString()); 

Here you reuse the key from the original dictionary and you convert the values to strings using the ToString method.

If your dictionary can contain null values you should add a null check before performing the ToString:

Dictionary<string, string> dString = dObject.ToDictionary(k => k.Key, k => k.Value == null ? "" : k.Value.ToString()); 

The reason this works is that the Dictionary<string, object> is actually an IEnumerable<KeyValuePair<string,object>>. The above code example iterates through the enumerable and builds a new dictionary using the ToDictionary method.

Edit:

In .Net 2.0 you cannot use the ToDictionary method, but you can achieve the same using a good old-fashioned foreach:

Dictionary<string, string> sd = new Dictionary<string, string>();  foreach (KeyValuePair<string, object> keyValuePair in dict) {   sd.Add(keyValuePair.Key, keyValuePair.Value.ToString()); } 

Edit2:

If you are on .Net 2.0 and you can have null values in the dictionary the following should be safe:

Dictionary<string, string> sd = new Dictionary<string, string>();  foreach (KeyValuePair<string, object> keyValuePair in dict) {   sd.Add(keyValuePair.Key, keyValuePair.Value == null ? "" : keyValuePair.Value.ToString()); } 

Answer 2

.NET 3.5:

Dictionary<string, string> result = dObject.ToDictionary(kvp => kvp.Key, kvp => Convert.ToString(kvp.Value)); 

.NET 2.0:

Dictionary<string, string> result = new Dictionary<string, string>(); foreach (KeyValuePair<string, object> kvp in dObject) result.Add(kvp.Key, Convert.ToString(kvp.Value));