Fixed duplicate input name

Author: ArshaGDS

Diff for: .vs/DNSManager/DesignTimeBuild/.dtbcache.v2

@@ -93,6 +93,12 @@ private void buttonAdd_Click(object sender, EventArgs e)
                 return;
             }
 
+            if (checkName(name))
+            {
+                MessageBox.Show("The DNS name must not be duplicated.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                return;
+            }
+
             if (!IsDnsFormatValid(dns1) && !IsDnsFormatValid(dns2))
             {
                 MessageBox.Show("Please enter valid format.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
@@ -118,6 +124,26 @@ private void insert(string name, string dns1, string dns2)
             insertCommand.ExecuteNonQuery();
         }
 
+        private bool checkName(string name)
+        {
+
+            var selectQuery = "SELECT Name FROM DNS";
+            var selectCommand = new SQLiteCommand(selectQuery, _connection);
+            var reader = selectCommand.ExecuteReader();
+
+            while (reader.Read())
+            {
+                if (reader.GetString(0) == name)
+                {
+                    return true;
+                }
+            }
+
+            reader.Close();
+
+            return false;
+        }
+
         private void buttonDelete_Click(object sender, EventArgs e)
         {
             var name = comboBoxDNS.SelectedItem?.ToString();

Diff for: .vs/DNSManager/FileContentIndex/0d3a429c-58fe-41c6-b867-881d20aa0d41.vsidx

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+https://go.microsoft.com/fwlink/?LinkID=208121.
+-->
+<Project>
+  <PropertyGroup>
+    <ApplicationRevision>0</ApplicationRevision>
+    <ApplicationVersion>0.1.0.*</ApplicationVersion>
+    <BootstrapperEnabled>True</BootstrapperEnabled>
+    <Configuration>Release</Configuration>
+    <CreateWebPageOnPublish>False</CreateWebPageOnPublish>
+    <GenerateManifests>true</GenerateManifests>
+    <Install>True</Install>
+    <InstallFrom>Disk</InstallFrom>
+    <IsRevisionIncremented>True</IsRevisionIncremented>
+    <IsWebBootstrapper>False</IsWebBootstrapper>
+    <MapFileExtensions>True</MapFileExtensions>
+    <OpenBrowserOnPublish>False</OpenBrowserOnPublish>
+    <Platform>Any CPU</Platform>
+    <PublishDir>bin\Release\net6.0-windows\app.publish\</PublishDir>
+    <PublishUrl>bin\publish\</PublishUrl>
+    <PublishProtocol>ClickOnce</PublishProtocol>
+    <PublishReadyToRun>False</PublishReadyToRun>
+    <PublishSingleFile>False</PublishSingleFile>
+    <SelfContained>False</SelfContained>
+    <SignatureAlgorithm>(none)</SignatureAlgorithm>
+    <SignManifests>False</SignManifests>
+    <TargetFramework>net6.0-windows</TargetFramework>
+    <UpdateEnabled>False</UpdateEnabled>
+    <UpdateMode>Foreground</UpdateMode>
+    <UpdateRequired>False</UpdateRequired>
+    <WebPageFileName>Publish.html</WebPageFileName>
+  </PropertyGroup>
+  <ItemGroup>
+    <BootstrapperPackage Include="Microsoft.NetCore.DesktopRuntime.6.0.x64">
+      <Install>True</Install>
+      <ProductName>.NET Desktop Runtime 6.0.14 (x64)</ProductName>
+    </BootstrapperPackage>
+  </ItemGroup>
+</Project>

Diff for: .vs/DNSManager/FileContentIndex/5435778e-6364-4372-9766-e70a055ccb10.vsidx

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+https://go.microsoft.com/fwlink/?LinkID=208121.
+-->
+<Project>
+  <PropertyGroup>
+    <History>False|2023-05-22T00:11:32.2299052Z;</History>
+    <LastFailureDetails />
+  </PropertyGroup>
+</Project>