# IfField.Expression1 Property

> Gets and sets the first expression text that should be compared. To use this field in the MailMerge component, this property must be a valid field name.

- **Product:** TX Text Control .NET Server
- **Section:** Reference
- **Kind:** Property
- **Introduced:** 15.0
- **Namespace:** `TXTextControl.DocumentServer.Fields`
- **Package:** `TXTextControl.TextControl.Core.SDK` (assembly `TXDocumentServer.Core.dll`, from the private NuGet feed or Text Control Offline Packages)
- **Package:** `TXTextControl.TextControl.ASP.SDK` (assembly `TXDocumentServer.dll`, from the private NuGet feed or Text Control Offline Packages)
- **.NET Framework:** reference `TXDocumentServer.dll` from the setup
- **Path:** TX Text Control .NET Server > Reference > TXTextControl.DocumentServer.Fields > IfField.Expression1 Property
- **434 words**
- **Web URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-fields/iffield/expression1-property/
- **LLMs URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-fields/iffield/expression1-property/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-fields/iffield/expression1-property/llms-full.txt

---

### Description

Gets and sets the first expression text that should be compared. To use this field in the [MailMerge](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver/mailmerge/llms-full.txt) component, this property must be a valid field name.

### Syntax

```csharp
public string Expression1 { get; set; }
```

```vbnet
Public Property Expression1 As String
```

### Examples

The following example uses `IfField.Expression1` to configure expression1 as part of the if field workflow. The configured value is checked before the workflow continues.

```csharp
ifField.Expression1 = "Quarterly report";
if (!string.IsNullOrWhiteSpace(ifField.Expression1))
{
    Console.WriteLine($"Expression1: {ifField.Expression1}");
}
```

```vbnet
ifField.Expression1 = "Quarterly report"
If Not String.IsNullOrWhiteSpace(ifField.Expression1) Then
    Console.WriteLine($"Expression1: {ifField.Expression1}")
End If
```

---

## Nearby

- **Previous:** [IfField.DataSourceCulture Property](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-fields/iffield/datasourceculture-property/llms-full.txt)
- **Next:** [IfField.Expression2 Property](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/txtextcontrol-documentserver-fields/iffield/expression2-property/llms-full.txt)