How I can get all themes and set specific theme of SharePoint online

Question

I have tried to get all themes of SharePoint online using ClientObjectList themes = tenant.GetAllTenantThemes(); but failed.

I have tried this code but failed to get

using System.Security;
using Microsoft.SharePoint.Client;
using Microsoft.Online.SharePoint.TenantAdministration;
using Microsoft.Online.SharePoint.TenantManagement;

...

ClientContext ctx = new ClientContext("https://mysite-admin.sharepoint.com/");
var pwd = "mypassword";
var passWord = new SecureString();
foreach (char c in pwd.ToCharArray()) passWord.AppendChar(c);
ctx.Credentials = new SharePointOnlineCredentials("admin@mydomain.com", passWord);
Tenant tenant = new Tenant(ctx);
ClientObjectList<ThemeProperties> themes = tenant.GetAllTenantThemes();

Error is: The collection has not been initialized. It has not been requested or the request has not been executed. It may need to be explicitly requested.

Answer 1

Use the code below to get all themes in tenant. Note: add ctx.load and ctx.ExecuteQuery methods.

string siteUrl = "https://tenant-admin.sharepoint.com";
string userName = "lz@tenant.onmicrosoft.com";
string password = "xxx";
var securePassword = new SecureString();
foreach (char c in password.ToCharArray()) securePassword.AppendChar(c);
using (ClientContext ctx = new ClientContext(siteUrl))
{
    ctx.Credentials = new SharePointOnlineCredentials(userName, securePassword);               
    Tenant tenant = new Tenant(ctx);
    ClientObjectList<ThemeProperties> themes = tenant.GetAllTenantThemes();
    ctx.Load(themes);
    ctx.ExecuteQuery();
    foreach(ThemeProperties pres in themes)
    {
        Console.WriteLine(pres.Name);
    }
}

We can also use Pnp PowerShell to achieve it.

Get-PnPTenantTheme

Add-PnPTenantTheme

Set Theme for a site using this.

tenant.SetWebTheme("Custom Black", "http://tenant.sharepoint.com/sites/TestModernTeamSite6");
ctx.ExecuteQueryRetry();