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使用C查找所有空的文本框和组合框#

visual-studio c#

ras bry · 技术社区 · 2 年前

大家好,我想以一种简单的方式找到所有空的TextBox和ComboBox。如下图所示,如果字段为空,则显示文本框或组合框为空的消息和红色背景色。

我试过了,但出了问题,感谢那些能解决这个问题的人。

        TextBox [] textBox = { textBox1, textBox2};
        ComboBox[] comboBox = { comboBox1, comboBox2 };

        foreach (TextBox txt in textBox)
        {
            if (string.IsNullOrEmpty(txt.Text))//if all textbox is empty
            {
                txt.BackColor = Color.Red;
                string message = "Required field empty.";
                string tittle = "Error";
                MessageBoxButtons button = MessageBoxButtons.OK;
                DialogResult result = MessageBox.Show(message, tittle, button, MessageBoxIcon.Error);
                break;

            }
            else if (!string.IsNullOrEmpty(txt.Text))//if not empty
            {

                txt.BackColor = Color.White;
                MessageBox.Show("task complete");
                break;
            }

        }
        return;

2 回复 | 直到 2 年前

Suryateja KONDLA 2 年前

// Arrays to hold your TextBox and ComboBox controls
TextBox[] textBoxes = { textBox1, textBox2 };
ComboBox[] comboBoxes = { comboBox1, comboBox2 };

bool isEmpty = false; // Flag to indicate if any field is empty

// Check each TextBox
foreach (TextBox txt in textBoxes)
{
    if (string.IsNullOrEmpty(txt.Text))
    {
        txt.BackColor = Color.Red;
        isEmpty = true;
    }
    else
    {
        txt.BackColor = Color.White;
    }
}

// Check each ComboBox
foreach (ComboBox cmb in comboBoxes)
{
    if (string.IsNullOrEmpty(cmb.Text))
    {
        cmb.BackColor = Color.Red;
        isEmpty = true;
    }
    else
    {
        cmb.BackColor = Color.White;
    }
}

// Show a single message if any field is empty
if (isEmpty)
{
    string message = "Required field empty.";
    string title = "Error";
    MessageBoxButtons buttons = MessageBoxButtons.OK;
    MessageBox.Show(message, title, buttons, MessageBoxIcon.Error);
}
else
{
    MessageBox.Show("Task complete");
}

Auditive 2 年前

您可以通过选择表单的所有控件 this.Controls ,然后使用LINQ进行过滤 Where 只取 TextBox 或 ComboBox 控件,以及 .Text 属性为空。

using System;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
// ...

private void ButtonSubmit_Click(object sender, EventArgs e)
{
    // Find and take from all controls of the form only TextBox'es and ComboBox'es, which .Text is empty
    var unfilledControls = this.Controls.Cast<Control>()
                           .Where(c => c is TextBox or ComboBox && string.IsNullOrEmpty(c.Text))
                           .ToList();

    // Check if there was found unfilled controls
    if (unfilledControls.Count == 0)
    {
        // Here you can proceed submit
        // DoSubmit();
        // MessageBox.Show("Submitted!");
        // this.Close(); // to close form, or...
        return;
    }
     
    // Here something is unfilled, so apply "warning" to control(s) or notify user
       
    unfilledControls.ForEach(c => c.BackColor = Color.Red);
    MessageBox.Show("Some required fields are empty!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}

看起来像:

您还可以通过设置“警告”行为 TextChanged 属性,例如,在形式构造函数中。只需将匿名委托应用于该事件。所以它会改变 BackColor 并“动态”检查用户输入。

public Form3()
{
    InitializeComponent();

    this.Controls.Cast<Control>()
    .Where(c => c is TextBox or ComboBox)
    .ToList()
    .ForEach(control =>
    {
         control.TextChanged += delegate
         {
             control.BackColor = string.IsNullOrEmpty(control.Text)
                ? Color.Red
                : Color.White;
         };
    });
}