This probably isn't ideal, but I just used the XML stored in the property. Try this:

var inBriefXml = new DynamicXml((string)Model.getProperty("inBrief").Value);
foreach (var item in inBriefXml)
{ 
 var xmlItem = item.BaseElement;
 @xmlItem.Element("inBriefText").Value
 @xmlItem.Element("inBriefTitle").Value
 // not sure what to do with the media picker...
}
 

I struggled with this too somewhat recently, back in an umbraco 4.11.8 site with uComponents v5.3.2. I ended up having to resort to accessing my values by ordinal index since I could never get the access-by-name to work.

Perhaps they've made this easier in the last five or so months since I last did this. And yes, this is somewhat brittle should you ever change the order of your datagrid fields or add/remove one, etc... But in any case, good luck to you!

@inherits umbraco.MacroEngines.DynamicNodeContext
@foreach(var row in Model.myProp)
{
    <tr>
        <td>@row.Cells[0].Value</td>
        <td>@row.Cells[1].Value</td>
        <td>@row.Cells[2].Value</td>
        <td>@row.Cells[3].Value</td>
    </tr>
}

Although this is an old post, I struggled with this recently and discovered that documentation has not improved much with the very useful and powerful DataType Grid. However, I am posting this code snippet in hopes of helping the next person.

Assuming that my DataType Grid has an alias of "myDTGrid" with the following datatype aliases contained within - textString1, textString2, mediaChoice:

@inherits umbraco.MacroEngines.DynamicNodeContext
@{
    if (Model.HasProperty("myDTGrid") && Model.HasValue("myDTGrid"))
    {
        foreach (var row in Model.myDTGrid)
        {
            <div>@row.textString1</div>
            <div>@row.textString2</div>
           @if (row.mediaChoice != null)
           {
               dynamic selectedMedia = @Library.MediaById(row.mediaChoice);
               if (selectedMedia != null && selectedMedia.Id > 0 && selectedMedia.HasProperty("umbracoFile") && selectedMedia.HasValue("umbracoFile"))
               {
                   <img src="@selectedMedia.umbracoFile" />
               }
           }
            <div>@row.textString1</div>

        }
    }
}

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