InvalidElementStateException when attempting to clear text through Selenium

The web application I am testing requires confirmation when deleting a record.

I have created a test to enter in a valid reason for deleting this record.

The code to do this is as follows:

DeleteFieldButton.
            Click();
        WaitMethods.WaitForElementToBeDisplayed(RemovalReason, 20);
        RemovalReason
            .Click();
        RemovalReason
            .Clear();
        RemovalReason
            .SendKeys("Automated Test - Delete Field");

The XPath to the text box is as follows:

private Label RemovalReason = new Label(By.XPath("//*[@placeholder = 'Removal reason']"));

Whenever the test is run the following exception is returned.

OpenQA.Selenium.InvalidElementStateException
HResult=0x80131500
Message=Cannot clear By.XPath: //*[@placeholder = 'Removal reason'] as it is 
not declared as a writable text element
Source=web
StackTrace:
at web.Elements.Common.Element.Clear()
at Daera.Efs.Test.E2e.PageObjects.ApplicationSummary.DeleteField(String 
FieldIDToDelete) in 
C:\Code\Local\WebApp.E2e\PageObjects\ApplicationSummary.cs:line 280
 at Test.E2e.Tests.ApplicationSummaryTest.Delete_Wider_General_Field_From_Application_Summary() in C:\Code\Local\WebApp.E2e\Tests\ApplicationSummaryTest.cs:line 45

Below is the HTML of the element on the web application:

<input ng-keypress="dialog.keypress($event)" md-autofocus="" ng-model="dialog.result" placeholder="Removal reason" class="ng-valid md-input ng-not-empty md-autofocus ng-touched ng-dirty ng-valid-parse" aria-label="Removal reason" id="input_22" aria-invalid="false" style="">

As per the HTML you have shared the <input> element with placeholder attribute as Removal reason is an Angular element and as you have to send text, you have to induce WebDriverWait for the element to be clickable as follows :

IWebElement myElem = new WebDriverWait(driver, TimeSpan.FromSeconds(10)).Until(ExpectedConditions.ElementToBeClickable(By.XPath("//input[@class='ng-valid md-input ng-not-empty md-autofocus ng-touched ng-dirty ng-valid-parse' and starts-with(@id,'input_') and @placeholder='Removal reason']")));
myElem.Click();
myElem.Clear();
myElem.SendKeys("Automated Test - Delete Field");

References

You can find a couple of relevant discussions in:

• How to clear text field before sending keys selenium c#
• clear() does not clear the textbox with selenium and python and firefox
• python selenium can't clear input field