How to Fix the 'Input String Was Not in a Correct Format' Error in a C# Calculator?

C#calculator "Incorrect input string format" error solution

In C#, trying to analyze the invalid string to numerical data type may cause the "input string format to incorrect" error. This error occurs when the string passed to the method does not meet the expected format of the target data type.

In a given C#calculator code, the error occurred because the Parse method is used in the constructor to convert the empty string (retrieved from the text box) to an integer. By default, the text box is empty when creating a window.

Solution: Parse

In order to solve this problem, the code should update the values ​​of and in the button click on the event, rather than in the constructor, because the text box contains meaningful values ​​in the button click event. In addition, the method should be used to process the string may not contain an effective integer.

It will not throw an exception to make it easier to deal with.

a The following is the modified code fragment: b TryParse TryParse This modification will change and

to

and

, which is more in line with the code style of modern C#, and clearly specifies the type of output parameters. More importantly, it adds a placeholder

<code class="language-csharp">// ... (不变的代码)

public Form1()
{
    InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
    if (Int32.TryParse(textBox1.Text, out int a))
    {
        // 执行加法运算
    }
    else
    {
        // 处理无效输入，例如显示错误消息
    }

    if (Int32.TryParse(textBox2.Text, out int b))
    {
        // 执行加法运算
    }
    else
    {
        // 处理无效输入，例如显示错误消息
    }

    add();
    result();
}
// ... (其余代码不变)</code>

when fails. It is recommended to add code here to process invalid input. For example, display a messagebox informing the user informing the error, or resetting the text box content to empty Essence This makes the program more robust and can better process the error data that users may enter.

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