winform怎么调取web接口

```csharp

using System;

using System.Net.Http;

using System.Threading.Tasks;

namespace WinFormWebApiExample

{

public partial class MainForm : Form

{

private HttpClient httpClient;

public MainForm()

{

InitializeComponent();

// 初始化HttpClient

httpClient = new HttpClient();

httpClient.BaseAddress = new Uri("http://api.example.com"); // 设置Web接口的基础地址

}

private async void btnGetData_Click(object sender, EventArgs e)

{

try

{

// 发送GET请求，并获取响应内容

HttpResponseMessage response = await httpClient.GetAsync("/api/data");

response.EnsureSuccessStatusCode();

string responseBody = await response.Content.ReadAsStringAsync();

// 处理响应内容

// ...

// 显示结果

tbResult.Text = responseBody;

}

catch (Exception ex)

{

tbResult.Text = "Error: " + ex.Message;

}

}

private async void btnSendData_Click(object sender, EventArgs e)

{

try

{

// 构造要发送的数据

var data = https://www.yisu.com/ask/new { Name = tbName.Text, Age = int.Parse(tbAge.Text) };

// 发送POST请求，并获取响应内容

HttpResponseMessage response = await httpClient.PostAsJsonAsync("/api/data", data);

response.EnsureSuccessStatusCode();

string responseBody = await response.Content.ReadAsStringAsync();

// 处理响应内容

// ...

// 显示结果

tbResult.Text = responseBody;

}

catch (Exception ex)

{

tbResult.Text = "Error: " + ex.Message;

}

}

}

}

```

在上面的示例中，MainForm是一个WinForm的主窗体类，其中有两个按钮分别用于获取数据和发送数据。在构造函数中初始化HttpClient并设置Web接口的基础地址。点击按钮时，通过HttpClient发送对应的HTTP请求并处理响应内容。注意要引入System.Net.Http和System.Threading.Tasks命名空间。