Convert an object to System Guid

Guid mainfolderid = (main.GetValue(""));

where main is a dynamic entity.

How can I convert the above mentioned main.GetValue("") to System.Guid?

The error says

Cannot implicitly convert type object to 'System.Guid'.开发者_JAVA百科

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Does the GetValue method actually return a Guid typed as object? If so, then you just need to perform an explicit cast like so:

Guid mainfolderid = (Guid)main.GetValue("");

If not, does GetValue return something that can be passed to one of the constructors (ie, a byte[] or string)? In that case you could do this:

Guid mainfolderid = new Guid(main.GetValue(""));

If neither of the above are applicable then you're going to need to do some manual work to convert whatever's returned by GetValue to a Guid.

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If you're using .Net 4.0, there were Parsing methods added to the Guid struct:

Guid Guid.Parse(string input)

and

bool Guid.TryParse(string input, out Guid result)

will do what you want.

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Guid mainfolderid = new Guid(main.GetValue("").ToString());

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One way is to use the GUID constructor, and pass it a string representation of the GUID. This will work if the object is really a string representation of GUID. Example:

Guid mainfolderid = new Guid(main.GetValue("").ToString());

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Guid mainfolderid = (Guid)(main.GetValue(""));

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Guid could be constructed by string representation, so this should work:

Guid result = new Guid(main.GetValue("").ToString());

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There are a solution using the Type of the objet:

GuidAttribute   guidAttr;
object[]        arrAttrs;
Type            type;
string          strGuid;

type = main.GetType();
arrAttrs = type.Assembly.GetCustomAttributes(typeof(System.Runtime.InteropServices.GuidAttribute), false);
guidAttr = (arrAttrs != null && arrAttrs.Length > 0) ? arrAttrs[0] as GuidAttribute: null;
if (guidAttr != null) {
    strGuid = "{" + guidAttr.Value.ToUpper() + "}";
}