You can see more than 8 lines (number of drop down lines you specified) are displayed in the drop-down list as below screenshot shown.

In my case I am using integer type for ng-model value which by default contains value as zero. The md-select should be valid but its still throwing an error that its required.

You can add an optional message to the drop-down list. Next, enter a Title and the Input message in the boxes.

validating drop down-10

Enter each option in a column (or row), one option to a cell. For this example, we want to add drop-down lists to the Rating column, or column B. In the Data Tools section, click the Data Validation button. On the Settings tab, you can have Excel restrict entries in the selected cells to dates, numbers, decimals, times, or a certain length.

Select the cells you want to add the drop-down lists too. For our example, select List from the Allow drop-down list to create a drop-down list in each of the selected cells.

If you try to enter an option that doesn’t match any of the preset options, the Error Alert you set up displays on a dialog box.

By default, a data validation drop-down list only shows 8 items in the list when clicking the drop-down arrow.

You can do that when you define the data validation or you can define a list in another location on the same worksheet or on another worksheet.

For this example, we’re going to list the options for the drop-down list on another worksheet so click one of the worksheet tabs at the bottom of the Excel window.In our example, when someone types an option into the cell that doesn’t match any of the preset options, the error message displays.To add an error message, click the Error Alert tab.This example describes how to create dependent drop-down lists in Excel. On the Data tab, in the Data Tools group, click Data Validation. Here's what we are trying to achieve: The user selects Pizza from a drop-down list. As a result, a second drop-down list contains the Pizza items.