IMap::Lookup method

项目
02/13/2018

Returns the item at the specified key in the IMap.

Syntax

HRESULT Lookup(
  [in]  K key,
  [out] V *value
);

Parameters

key [in]
Type: K

The key to use to locate the item in the IMap.
value [out]
Type: V*

The item associated with the specified key.

Return value

Type: HRESULT

If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

Use the HasKey method to determine if the key exists in the map.

Examples

The following code example demonstrates how to use the Lookup method.

comptr<IMap<HSTRING,IValue>> pMap;
HSTRING hKey;
//...

comptr<IMapView<HSTRING,IValue>> pMapView;
HRESULT hr = pMap->GetView(&pMapView);
if (SUCCEEDED(hr))
{
    bool bHasKey
    hr = pMapView->HasKey(hKey, &bHasKey);
    if (SUCCEEDED(hr) && bHasKey)
    {
        comptr<IValue> pValue;
        hr = pMapView->Lookup(hKey, &pValue);
        if (SUCCEEDED(hr))
        {
            //...
        }
    }
}

Requirements

Minimum supported client	Windows 8
Minimum supported server	Windows Server 2012
Header	Windows.Foundation.Collections.h

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