data validation: add list dropdown toggle

Feature #97

src/data_validation.rs

@@ -182,6 +182,7 @@ pub struct DataValidation {
     pub(crate) ignore_blank: bool,
     pub(crate) show_input_message: bool,
     pub(crate) show_error_message: bool,
+    pub(crate) show_dropdown: bool,
     pub(crate) multi_range: String,
     pub(crate) input_title: String,
     pub(crate) error_title: String,
@@ -205,6 +206,7 @@ impl DataValidation {
             ignore_blank: true,
             show_input_message: true,
             show_error_message: true,
+            show_dropdown: true,
             multi_range: String::new(),
             input_title: String::new(),
             error_title: String::new(),
@@ -986,6 +988,28 @@ impl DataValidation {
         self
     }
 
+    /// Turn on/off the in-cell dropdown for list data validations.
+    ///
+    /// By default the Excel list data validation has an "In-cell drop-down"
+    /// option turned on. This shows a dropdown arrow for list style data
+    /// validations and displays the list items.
+    ///
+    /// <img
+    /// src="https://rustxlsxwriter.github.io/images/data_validation_allow_list_strings_dialog.png">
+    ///
+    /// If this option is turned off the data validation will restrict input to
+    /// the specified list values but it won't display a visual indicator of
+    /// what those values are.
+    ///
+    /// # Parameters
+    ///
+    /// * `enable` - Turn the property on/off. It is on by default.
+    ///
+    pub fn show_dropdown(mut self, enable: bool) -> DataValidation {
+        self.show_dropdown = enable;
+        self
+    }
+
     /// Toggle option to show an input message when the cell is entered.
     ///
     /// This function is used to toggle the option that controls whether an

src/data_validation/tests.rs

@@ -1630,4 +1630,45 @@ mod data_validation_tests {
 
         Ok(())
     }
+
+    #[test]
+    fn data_validation_27() -> Result<(), XlsxError> {
+        let mut worksheet = Worksheet::new();
+        worksheet.set_selected(true);
+
+        let data_validation = DataValidation::new()
+            .allow_list_strings(&["Foo", "Bar", "Baz"])?
+            .show_dropdown(false);
+
+        worksheet.add_data_validation(0, 0, 0, 0, &data_validation)?;
+
+        worksheet.assemble_xml_file();
+
+        let got = worksheet.writer.read_to_str();
+        let got = xml_to_vec(got);
+
+        let expected = xml_to_vec(
+            r#"
+            <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+            <worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">
+              <dimension ref="A1"/>
+              <sheetViews>
+                <sheetView tabSelected="1" workbookViewId="0"/>
+              </sheetViews>
+              <sheetFormatPr defaultRowHeight="15"/>
+              <sheetData/>
+              <dataValidations count="1">
+                <dataValidation type="list" allowBlank="1" showDropDown="1" showInputMessage="1" showErrorMessage="1" sqref="A1">
+                  <formula1>"Foo,Bar,Baz"</formula1>
+                </dataValidation>
+              </dataValidations>
+              <pageMargins left="0.7" right="0.7" top="0.75" bottom="0.75" header="0.3" footer="0.3"/>
+            </worksheet>
+            "#,
+        );
+
+        assert_eq!(expected, got);
+
+        Ok(())
+    }
 }

src/worksheet.rs

@@ -13462,6 +13462,10 @@ impl Worksheet {
             attributes.push(("allowBlank", "1".to_string()));
         }
 
+        if !data_validation.show_dropdown {
+            attributes.push(("showDropDown", "1".to_string()));
+        }
+
         if data_validation.show_input_message {
             attributes.push(("showInputMessage", "1".to_string()));
         }
@@ -13519,6 +13523,10 @@ impl Worksheet {
             attributes.push(("allowBlank", "1".to_string()));
         }
 
+        if !data_validation.show_dropdown {
+            attributes.push(("showDropDown", "1".to_string()));
+        }
+
         if data_validation.show_input_message {
             attributes.push(("showInputMessage", "1".to_string()));
         }