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?
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6 Answers
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());
}
13 Comments
Manoj Singh
I am using .NET 2.0, is possible in it. I am not getting "ToDictionary"
Oscar Mederos
@Rune: Will
k.Value.ToString() return always the same as (string)k.Value?
Rune Grimstad
@Oscar: No. the (string)k.Value will fail if the value is a non-string object. The ToString() is safe for all non-null values.
Oscar Mederos
@Rune: Yes, I know that. Let's suppose all elements are strings. Will
ToString() and (string) return the same?
Jeff Mercado
Might I suggest using
Convert.ToString() instead. So it will be a little easier to deal with null values. Convert.ToString(keyValuePair.Value) or Convert.ToString(keyValuePair.Value) ?? String.Empty |
.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));
Comments
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
}
3 Comments
Manoj Singh
What if there is NULL values in it?
Cheng Chen
@MKS: That's why I'm saying "convert your item to string according to the requirement", for example you can use
string.Empty for null values, or the string "NULL" for null values...everything depends on the requirement.Manoj Singh
Sometime there can be null values also in the key, please suggest how to convert it?
How about:
Dictionary<string, string> newDictionary = dObject.ToDictionary(k => k.Key, k => (string) k.Value);
5 Comments
Rune Grimstad
This will fail if the dictionary contains non-string values. You cannot convert an int to a string for instance.
Manoj Singh
First of all I am using .NET 2.0, is possible in it. I am not getting "ToDictionary" method.
Oscar Mederos
Well, I suppose if he wants to do it is because the dictionary contains
strings, but anyway, that's valid.
Arcturus
Yeah true.. But ToString does not always produce a nice string. It all depends on your Dictionary objects anyhow. :)
Arcturus
Since you are using .NET 2.0, foreach will be your bestest buddy! GL
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());
}
Comments
Dictionary<string, string> dString = dObject.ToDictionary(kvp => kvp.Key, kvp => kvp.Value.ToString());
It's just idea. You can insert any verifications.
