causesvalidation（这里加上CausesValidation=“True“ 具体有什么用）

本文目录

• 这里加上CausesValidation=“True“ 具体有什么用
• asp.net中，CauseValidation是什么意思

这里加上CausesValidation=“True“ 具体有什么用

这个界面上应该有验证控件， 你这个按钮应该是在一个列表控件里的吧。说明要想进入这个列表的后台，先对列表的某一个输入的值进行了验证！通过了才进入后台！

asp.net中，CauseValidation是什么意思

Control.CausesValidation 属性

获取或设置一个值，该值指示控件是否会引起在任何需要在接收焦点时执行验证的控件上执行验证。

下面的代码示例创建一个 Windows 窗体，该窗体添加在文本框中输入的数字。在显示结果之前会先验证文本框。

private void AddHandlers()
{
// Add the Validating and Validated handlers for textboxes.
myTextBox1.Validating +=
new System.ComponentModel.CancelEventHandler(myTextBox1_Validating);
myTextBox1.Validated +=
new System.EventHandler(myTextBox1_Validated);
myTextBox2.Validating +=
new System.ComponentModel.CancelEventHandler(myTextBox2_Validating);
myTextBox2.Validated +=
new System.EventHandler(myTextBox2_Validated);
myTextBox1.CausesValidationChanged +=
new System.EventHandler(myTextBox1_CausesValidationChanged);
myTextBox2.CausesValidationChanged +=
new System.EventHandler(myTextBox2_CausesValidationChanged);
if(myTextBox1.CausesValidation == true && myTextBox2.CausesValidation == true)
{
button1.Text = “Disable Validation“;
myLabel.Text = “Validation Enabled“;
this.Focus();
}
}
private void myTextBox1_Validating(object sender,System.ComponentModel.CancelEventArgs e)
{
if(!CheckIfTextBoxNumeric(myTextBox1))
{
myLabel.Text = “Has to be numeric“;
e.Cancel = true;
}
}
private void myTextBox1_Validated(object sender,System.EventArgs e)
{
myLabel.Text = “Validated first control“;
}
private void myTextBox2_Validating(object sender,System.ComponentModel.CancelEventArgs e)
{
if(!CheckIfTextBoxNumeric(myTextBox2))
{
myLabel.Text = “Has to be numeric“;
e.Cancel = true;
}
}
private void myTextBox2_Validated(object sender,System.EventArgs e)
{
myLabel.Text = “Validated second control“;
}
private void myTextBox1_CausesValidationChanged(object sender,System.EventArgs e)
{
myLabel.Text = “CausesValidation property was changed for First Textbox“;
}
private void myTextBox2_CausesValidationChanged(object sender,System.EventArgs e)
{
myLabel.Text = “CausesValidation property was changed for Second Textbox“;
}
private bool CheckIfTextBoxNumeric(TextBox myTextBox1)
{
bool isValid = true;
if(myTextBox1.Text == ““)
{
isValid = false;
}
else
{
for(int i=0; i《 myTextBox1.Text.Length;i++)
{
if(!(System.Char.IsNumber(myTextBox1.Text[i])))
{
myTextBox1.Text = ““;
isValid = false;
break;
}
}
}
return isValid;
}
private void myButtonAdd_Click(object sender, System.EventArgs e)
{
try
{
int result = Convert.ToInt32(myTextBox1.Text) + Convert.ToInt32(myTextBox2.Text);
myLabel.Text = result.ToString();
}
catch(Exception myException)
{
myLabel.Text = “Exception : “ + myException.Message;
}
}

private void button1_Click(object sender, System.EventArgs e)
{
if(myTextBox1.CausesValidation == false && myTextBox2.CausesValidation == false)
{
myTextBox1.CausesValidation = true;
myTextBox2.CausesValidation = true;
button1.Text = “Disable Validation“;
myLabel.Text = “Validation Enabled“;
}
else if(myTextBox1.CausesValidation == true && myTextBox2.CausesValidation == true)
{
myTextBox1.CausesValidation = false;
myTextBox2.CausesValidation = false;
button1.Text = “Enable Validation“;
myLabel.Text = “Validation Disabled“;
}
}