Guide Method Set Topic View Column Mode 1,2,3 Column

You can choose topic display in one ,two or three column

1. Add Column in database
     alter TABLE [dbo].[Topic]
     add [Template] [int] NULL CONSTRAINT [DF_Topic_Template]  DEFAULT ((1))

2. Goto Source code

2.1 Goto Libraries => Nop.Core => Domain => Topics => Topic.cs
    add this line   "public virtual int Template { get; set; }"

2.2 Goto Libraries => Nop.Data => Mapping => Topics => TopicMap.cs
    add this line    "this.Property(t => t.Template);" in constructor TopicMap()


3. Goto Presentation
3.1 Goto Nop.Web => Models => Topics => TopicModel.cs
    add this line "public int Template { get; set; }"

3.2 Goto Nop.Web => Views => Topic => TopicDeatils.cshtml
    Find in if (isPopup == null || isPopup == false){ ................ }
and replace
   if (isPopup == null || isPopup == false)
    {
        if (Model.Template == 1)
        {
            Layout = "~/Views/Shared/_ColumnsOne.cshtml";
        }
        else if (Model.Template == 2)
        {
            Layout = "~/Views/Shared/_ColumnsTwo.cshtml";
        }
        else
        {
            Layout = "~/Views/Shared/_ColumnsThree.cshtml";
        }
    }

4 go to Nop web admin and add resource Name "Admin.ContentManagement.Topics.Fields.TemplateColumn" Value "Tamplate"
4.1 Goto Nop.Admin => Models => Topics => TopicModel.cs
add this line "[NopResourceDisplayName("Admin.ContentManagement.Topics.Fields.TemplateColumn")]
        [AllowHtml]
        public int Template { get; set; }"
in class TopicModel

4.2 Goto Nop.Admin => Views => Topic => _CreateOrUpdate.cshtml
4.2.1 Find text  <tr id="pnlPasswordEnabled">
            <td class="adminTitle">
                @Html.NopLabelFor(model => model.Password):
            </td>
            <td class="adminData">
                @Html.EditorFor(model => model.Password)
                @Html.ValidationMessageFor(model => model.Password)
            </td>
        </tr>
4.2.2 and add this line under text 4.2.1
<tr id="pnlTemplateColumn">
            <td class="adminTitle">
                @Html.NopLabelFor(model => model.Template):
            </td>
            <td class="adminData">
                @Html.EditorFor(model => model.Template)
                @Html.ValidationMessageFor(model => model.Template)
            </td>
        </tr>

5. Save All and Run