From 57bb0491111df4d38c2c344eede574563da4d103 Mon Sep 17 00:00:00 2001
From: Edward Miller <edward.miller@mesirow.com>
Date: Fri, 17 May 2024 22:41:53 -0500
Subject: [PATCH 1/3] open XLS as read-only

---
 Public/ConvertTo-ExcelXlsx.ps1 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Public/ConvertTo-ExcelXlsx.ps1 b/Public/ConvertTo-ExcelXlsx.ps1
index 36c67c47..5191d176 100644
--- a/Public/ConvertTo-ExcelXlsx.ps1
+++ b/Public/ConvertTo-ExcelXlsx.ps1
@@ -46,7 +46,7 @@ function ConvertTo-ExcelXlsx {
         }
 
         $Excel.Visible = $false
-        $null = $Excel.Workbooks.Open($xlsFile.FullName)
+        $null = $Excel.Workbooks.Open($xlsFile.FullName, $null, $true)
         $Excel.ActiveWorkbook.SaveAs($xlsxPath, $xlFixedFormat)
         $Excel.ActiveWorkbook.Close()
         $Excel.Quit()

From 722516de7c22df0e5923824dc47a5f8007dc3d34 Mon Sep 17 00:00:00 2001
From: Edward Miller <edward.miller@mesirow.com>
Date: Fri, 17 May 2024 23:24:11 -0500
Subject: [PATCH 2/3] use try-finally

---
 Public/ConvertTo-ExcelXlsx.ps1 | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/Public/ConvertTo-ExcelXlsx.ps1 b/Public/ConvertTo-ExcelXlsx.ps1
index 5191d176..4abdc208 100644
--- a/Public/ConvertTo-ExcelXlsx.ps1
+++ b/Public/ConvertTo-ExcelXlsx.ps1
@@ -45,11 +45,15 @@ function ConvertTo-ExcelXlsx {
             throw "Could not create Excel.Application ComObject. Please verify that Excel is installed."
         }
 
-        $Excel.Visible = $false
-        $null = $Excel.Workbooks.Open($xlsFile.FullName, $null, $true)
-        $Excel.ActiveWorkbook.SaveAs($xlsxPath, $xlFixedFormat)
-        $Excel.ActiveWorkbook.Close()
-        $Excel.Quit()
+        try {  
+            $Excel.Visible = $false
+            $null = $Excel.Workbooks.Open($xlsFile.FullName, $null, $true)
+            $Excel.ActiveWorkbook.SaveAs($xlsxPath, $xlFixedFormat)
+        }
+        finally {
+            $Excel.ActiveWorkbook.Close()
+            $Excel.Quit()
+        }
     }
 }
 

From 36b5495bd50fa5a78b5452b43e1def51055334f8 Mon Sep 17 00:00:00 2001
From: Edward Miller <edward.miller@mesirow.com>
Date: Fri, 17 May 2024 23:28:26 -0500
Subject: [PATCH 3/3] check for null first

---
 Public/ConvertTo-ExcelXlsx.ps1 | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Public/ConvertTo-ExcelXlsx.ps1 b/Public/ConvertTo-ExcelXlsx.ps1
index 4abdc208..578445e0 100644
--- a/Public/ConvertTo-ExcelXlsx.ps1
+++ b/Public/ConvertTo-ExcelXlsx.ps1
@@ -51,7 +51,10 @@ function ConvertTo-ExcelXlsx {
             $Excel.ActiveWorkbook.SaveAs($xlsxPath, $xlFixedFormat)
         }
         finally {
-            $Excel.ActiveWorkbook.Close()
+            if ($null -ne $Excel.ActiveWorkbook) {
+                $Excel.ActiveWorkbook.Close()
+            }
+            
             $Excel.Quit()
         }
     }