Add validation for cutoff score in ImportPeptideSearchDlg

For whatever reason the cutoff score field in the "Import Peptide Search" dialog has never had any validation code, just cleaning that up. 

Not reported by any user.

pwiz_tools/Skyline/FileUI/PeptideSearch/BuildPeptideSearchLibraryControl.cs

@@ -281,11 +281,40 @@ public void AddSearchFiles(IEnumerable<string> fileNames)
             SearchFilenames = BuildLibraryDlg.AddInputFiles(WizardForm, SearchFilenames, fileNames, PerformDDASearch);
         }
 
+        // For test purposes, lets us test error handling
+        public string CutOffScoreText
+        {
+            set { textCutoff.Text = value; } // Can be a null or empty string under some circumstances
+        }
+
+        public bool NeedsCutoffScore => comboInputFileType.SelectedIndex > 0; // Only needed if Skyline is conducting the search
+
+        private double? _cutoffScore; // May be null when Skyline is not doing the search
+
         public double? CutOffScore
         {
             // Only valid when Skyline performs the search
-            get { return comboInputFileType.SelectedIndex > 0 ? double.Parse(textCutoff.Text) : (double?) null; }
-            set { textCutoff.Text = value.HasValue ? value.Value.ToString(CultureInfo.CurrentCulture) : string.Empty; }
+            get { return NeedsCutoffScore ? _cutoffScore : null; }
+            set
+            {
+                _cutoffScore = value;
+                textCutoff.Text = _cutoffScore.HasValue ? _cutoffScore.Value.ToString(CultureInfo.CurrentCulture) : string.Empty;
+            }
+        }
+
+        public bool ValidateCutoffScore()
+        {
+            if (!NeedsCutoffScore)
+            {
+                return true; // Doesn't matter what's in the text box, we won't use it
+            }
+            var helper = new MessageBoxHelper(this.ParentForm);
+            if (helper.ValidateDecimalTextBox(textCutoff, out var cutoffScore))
+            {
+                _cutoffScore = cutoffScore;
+                return true;
+            }
+            return false;
         }
 
         public bool IncludeAmbiguousMatches
@@ -643,5 +672,6 @@ private void comboInputFileType_SelectedIndexChanged(object sender, EventArgs e)
         {
             UpdatePerformDDASearch();
         }
+
     }
 }

pwiz_tools/Skyline/FileUI/PeptideSearch/ImportPeptideSearchDlg.cs

@@ -485,6 +485,10 @@ private void NextPage()
                     {
                         _pagesToSkip.Clear();
 
+                        if (!BuildPepSearchLibControl.ValidateCutoffScore())
+                        {
+                            return;
+                        }
                         ImportPeptideSearch.IsDDASearch = BuildPepSearchLibControl.PerformDDASearch;
                         ImportFastaControl.IsDDASearch = BuildPepSearchLibControl.PerformDDASearch;
                         if (!BuildPepSearchLibControl.UseExistingLibrary)

pwiz_tools/Skyline/TestFunctional/DdaSearchTest.cs

@@ -224,17 +224,24 @@ private void TestSearch()
             // Add the test xml file to the search files list and try to 
             // build the document library.
 
-            RunUI(() =>
+            var errMsgDlg = ShowDialog<MessageDlg>(() =>
             {
                 Assert.IsTrue(importPeptideSearchDlg.CurrentPage == ImportPeptideSearchDlg.Pages.spectra_page);
                 importPeptideSearchDlg.BuildPepSearchLibControl.PerformDDASearch = true;
                 importPeptideSearchDlg.BuildPepSearchLibControl.DdaSearchDataSources = SearchFiles.Select(o => (MsDataFileUri)new MsDataFilePath(o)).Take(1).ToArray();
                 importPeptideSearchDlg.BuildPepSearchLibControl.WorkflowType = ImportPeptideSearchDlg.Workflow.dia; // will go back and switch to DDA
-                importPeptideSearchDlg.BuildPepSearchLibControl.CutOffScore = 0.9;
+                importPeptideSearchDlg.BuildPepSearchLibControl.CutOffScoreText = @"12%"; // Intentionally bad 
                 importPeptideSearchDlg.BuildPepSearchLibControl.IrtStandards = IrtStandard.AUTO;
                 Assert.IsTrue(importPeptideSearchDlg.ClickNextButton());
             });
+            OkDialog(errMsgDlg, errMsgDlg.OkDialog); // Expect complaint about bad cutoff score
 
+            RunUI(() =>
+            {
+                Assert.IsTrue(importPeptideSearchDlg.CurrentPage == ImportPeptideSearchDlg.Pages.spectra_page); // Should not have advanced
+                importPeptideSearchDlg.BuildPepSearchLibControl.CutOffScore = 0.9;
+                Assert.IsTrue(importPeptideSearchDlg.ClickNextButton());
+            });
             // With only 1 source, no add/remove prefix/suffix dialog
 
             // We're on the "Match Modifications" page. Add M+16 mod.