diff --git a/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation.slnx b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation.slnx
new file mode 100644
index 00000000..c7397d5c
--- /dev/null
+++ b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation.slnx	
@@ -0,0 +1,3 @@
+<Solution>
+  <Project Path="UserDefinedValidation/UserDefinedValidation.csproj" />
+</Solution>
diff --git a/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/Data/InputTemplate.xlsx b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/Data/InputTemplate.xlsx
new file mode 100644
index 00000000..19956e03
Binary files /dev/null and b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/Data/InputTemplate.xlsx differ
diff --git a/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/Output/.gitkeep b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/Output/.gitkeep
new file mode 100644
index 00000000..e69de29b
diff --git a/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/Program.cs b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/Program.cs
new file mode 100644
index 00000000..261e1f29
--- /dev/null
+++ b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/Program.cs	
@@ -0,0 +1,38 @@
+using System.IO;
+using Syncfusion.XlsIO;
+
+namespace UserDefinedValidation
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            using (ExcelEngine excelEngine = new ExcelEngine())
+            {
+                IApplication application = excelEngine.Excel;
+                application.DefaultVersion = ExcelVersion.Xlsx;
+                IWorkbook workbook = application.Workbooks.Open(Path.GetFullPath(@"Data/InputTemplate.xlsx"));
+                IWorksheet worksheet = workbook.Worksheets[0];
+
+                //Data validation for the user-defined range
+                IDataValidation validation = worksheet.Range["C3"].DataValidation;
+                validation.AllowType = ExcelDataType.User;
+                validation.FirstFormula = "=Sheet1!$B$1:$B$3";
+                worksheet.Range["C1"].Text = "Data Validation List in C3";
+                worksheet.Range["C1"].AutofitColumns();
+               
+                //Shows the error message
+                validation.ErrorBoxText = "Choose the value from the list";
+                validation.ErrorBoxTitle = "ERROR";
+                validation.PromptBoxText = "Data validation for user-defined list";
+                validation.IsPromptBoxVisible = true;
+                validation.ShowPromptBox = true;
+
+                #region Save
+                //Saving the workbook
+                workbook.SaveAs(Path.GetFullPath(@"Output/ListValidation.xlsx"));
+                #endregion
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/UserDefinedValidation.csproj b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/UserDefinedValidation.csproj
new file mode 100644
index 00000000..39a86120
--- /dev/null
+++ b/Data Validation/UserDefinedValidation/.NET/UserDefinedValidation/UserDefinedValidation/UserDefinedValidation.csproj	
@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Syncfusion.XlsIO.Net.Core" Version="*" />
+  </ItemGroup>
+
+  <ItemGroup>
+	<None Update="Output\*">
+		<CopyToOutputDirectory>Always</CopyToOutputDirectory>
+	</None>
+	<None Update="Data\*">
+		<CopyToOutputDirectory>Always</CopyToOutputDirectory>
+	</None>
+  </ItemGroup>
+
+</Project>