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

问题

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?

回答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());
}

回答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));

回答3:

Since you are using .net 2.0:

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

foreach (KeyValuePair<string, object> item in dObject)
{
    dString.Add(item.Key, item.Value.ToString());
    //here item.Value.ToString() is an example
    //you should convert your item to string according to the requirement
}

回答4:

How about:

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

回答5:

In .Net 2.0 probably your best friend is foreach loop:

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

foreach (KeyValuePair<string, object> keyValuePair in dObject)
{
    newObjects.Add(keyValuePair.Key, keyValuePair.Value.ToString());
}

回答6:

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

It's just idea. You can insert any verifications.

来源：https://stackoverflow.com/questions/4942624/how-to-convert-dictionarystring-object-to-dictionarystring-string-in-c-sha