Write a error message if we cannot locate the CredentialStoreItem in the Store. Fix string quotation

src/Item/Set-CredentialStoreItem.ps1

@@ -13,7 +13,7 @@ function Set-CredentialStoreItem {
         Specify the host you for which you would like to change the credentials.
 
     .PARAMETER Identifier
-        Defaults to "". Specify a string, which separates two CredentialStoreItems for the
+        Defaults to ''. Specify a string, which separates two CredentialStoreItems for the
         same hostname.
 
     .PARAMETER Shared
@@ -30,10 +30,10 @@ function Set-CredentialStoreItem {
         [None]
 
     .EXAMPLE
-        Set-CredentialStoreItem -Path "C:\TMP\mystore.json" -RemoteHost "esx01.myside.local"
+        Set-CredentialStoreItem -Path 'C:\TMP\mystore.json' -RemoteHost 'esx01.myside.local'
 
     .EXAMPLE
-        Set-CredentialStoreItem -Path "C:\TMP\mystore.json" -RemoteHost "esx01.myside.local" -Identifier svc
+        Set-CredentialStoreItem -Path 'C:\TMP\mystore.json' -RemoteHost 'esx01.myside.local' -Identifier svc
     #>
 
     [CmdletBinding(DefaultParameterSetName = 'Private')]
@@ -65,7 +65,7 @@ function Set-CredentialStoreItem {
 
     begin {
         # Set the CredentialStore for private, shared or custom mode.
-        Write-Debug ("ParameterSetName: {0}" -f $PSCmdlet.ParameterSetName)
+        Write-Debug ('ParameterSetName: {0}' -f $PSCmdlet.ParameterSetName)
         if ($PSCmdlet.ParameterSetName -eq 'Private') {
             $Path = Get-DefaultCredentialStorePath
         }
@@ -77,32 +77,49 @@ function Set-CredentialStoreItem {
     }
 
     process {
-        # Lets do a quick test on the given CredentialStore.
-        if (-not(Test-CredentialStore -Shared -Path $Path)) {
+        # Define the default splatting.
+        $DefaultSplatting = @{
+            Path = $Path
+        }
+
+        # Check if the user passed -Shared. If he added -Shared, we'll pass it into the splatting
+        if ($PSCmdlet.ParameterSetName -eq 'Shared') {
+            $DefaultSplatting.Add('Shared', $true)
+        }
+
+        # Now lets check the given CredentialStore.
+        if (-not(Test-CredentialStore @DefaultSplatting)) {
             $MessageParams = @{
-                Message     = 'Could not add anything into the given CredentailStore.'
+                Message     = ('The given CredentialStore ({0}) does no exist.' -f $Path)
                 ErrorAction = 'Stop'
             }
             Write-Error @MessageParams
         }
 
         # Read the file content based on the given ParameterSetName
-        $CSContent = Get-CredentialStore -Shared -Path $Path
+        $CSContent = Get-CredentialStore @DefaultSplatting
 
+        # Get a formatted current date for the last update time of the Item.
         $CurrentDate = Get-Date -Format 'u'
 
-        if ($Identifier -ne "") {
-            $CredentialName = $RemoteHost = "{0}/{1}" -f $Identifier, $RemoteHost
+        # Check if the user supplied an identifier. If so, we need to mangle the CredentialName, as that's where
+        # the identifier is actually added.
+        if ($Identifier -ne '') {
+            $CredentialName = $RemoteHost = '{0}/{1}' -f $Identifier, $RemoteHost
         }
         else {
             $CredentialName = $RemoteHost
         }
 
+        # If the user didn't supply a CredentialObject, we need to prompt for it.
         if (-not($Credential)) {
             $Credential = Get-Credential -Message $CredentialName
         }
 
-        if ($Credential.UserName) {
+        # If the username isn't empty, we ca go ahead and update the entry.
+        if ($null -ne $Credential.UserName -and -not [string]::IsNullOrWhiteSpace($Credential.UserName)) {
+            # Check if the path to the PfxCertificate is stored in the CredentialStore. If so load the certificate.
+            # If not, load try loading the certificate from the Filepath of the CredentialStore.
             if ($null -eq $CSContent.PfxCertificate) {
                 $Cert = Get-CSCertificate -Type $CSContent.Type -Thumbprint $CSContent.Thumbprint
             }
@@ -110,13 +127,17 @@ function Set-CredentialStoreItem {
                 $Cert = Get-PfxCertificate -FilePath $CSContent.PfxCertificate -ErrorAction Stop
             }
 
+            # Now locate the Item.
             if (Get-Member -InputObject $CSContent -Name $CredentialName -MemberType Properties) {
+                # Get a random AES key for the entry.
                 $RSAKey = Get-RandomAESKey
                 $CSContent.$CredentialName.User = $Credential.UserName
                 $ConvertParams = @{
                     SecureString = $Credential.Password
                     Key          = $RSAKey
                 }
+
+                # Now create a updated item containing the updated credentials.
                 $CSContent.$CredentialName.Password = ConvertFrom-SecureString @ConvertParams
                 $CSContent.$CredentialName.LastChange = $CurrentDate
                 $CSContent.$CredentialName.EncryptedKey = [Convert]::ToBase64String(
@@ -125,10 +146,15 @@ function Set-CredentialStoreItem {
                         [System.Security.Cryptography.RSAEncryptionPadding]::Pkcs1
                     )
                 )
+
+                # Convert the CredentialStore back into JSON and save it to the file.
                 ConvertTo-Json -InputObject $CSContent -Depth 5 | Out-File -FilePath $Path -Encoding utf8
             }
+            else {
+                Write-Warning -Message ('Unable to locate CredentialStoreItem for {0}' -f $CredentialName)
+            }
         }
-        Else {
+        else {
             $MessageParams = @{
                 Message     = 'Please Provide at least a valid user!'
                 ErrorAction = 'Stop'