Want to get disabled select field value when form is submitted – Asp.net

You can try to use route parameter:

<form method="post" asp-route-ItemEditModel.ProjectJobId=@Model.ItemEditModel.ProjectJobId>
   ...
</form>

Or you can try to remove disabled before form submitting:

    <form id="myForm" method="post">
        <div class="form-group">
       <label asp-for="ItemEditModel.ProjectJobId" class="form-label required"></label>
          <div class="form-group">
             <select class="form-control" asp-for="ItemEditModel.ProjectJobId"
                                        asp-items="Model.ProjectJobList" disabled></select>
          </div>
          <span class="text-danger" asp-validation-for="ItemEditModel.ProjectJobId"></span>
    </div>
        <input type="submit" value="submit"/>
    </form>
<script>
$('#myForm').submit(function () {
            $("#ItemEditModel_ProjectJobId").removeAttr("disabled");
            return true; // return false to cancel form action
        });
</script>

Or you can add a hidden input to bind ItemEditModel.ProjectJobId:

<form method="post">
      <input hidden asp-for="ItemEditModel.ProjectJobId" />
      ...
</form>