如何使用Visual Studio和C＃将数据插入数据库并将其保存到数据库中？

Question

public string ss = "Data Source=D\\SQLEXPRESS;Initial Catalog=gym;Integrated Security=True";

private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
    string q2 = "insert into gym.dbo.customer (name, weight, height, add_class, gender, fees) values ('" + this.textBox1.Text + "','" + this.textBox2.Text + "','" + this.textBox3.Text + "','" + this.comboBox1.Text + "','" + this.comboBox2.Text + "','" + this.comboBox3.Text + " ') ;";

    SqlConnection con = new SqlConnection(ss);
    SqlCommand cmd = new SqlCommand(q2, con);
    SqlDataReader read;

    try
    {
        con.Open();
        read = cmd.ExecuteReader();
        MessageBox.Show("Welcome to our gym");

        while (read.Read()) { };
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

How can I insert and save data into the database using Visual Studio and C#?

This code throws an error. Anyone please give the suggestion to me to solve the error.

image description

Answer 1

At first make sure your the data type of different column of customer table. Then make sure what type of data you have to save for combobox.

you have to get the selected value from your Combobox. combobox1,combobox2,combobox3 retuns only the class name

 System.Windows.Forms.ComboBox

Besides others, it is recommended to use parameter .. like this: You can follow this example

private void button1_Click(object sender, EventArgs e)
{
    using(SqlConnection con = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=c:\users\abdul samad\documents\visual studio 2013\Projects\newpro\newpro\Database1.mdf;Integrated Security=True"))
    {
        try
        {

            using (var cmd = new SqlCommand("INSERT INTO registor (Name, FullName, Password, Email, Gander) VALUES (@Name,@Fullname,@Password,@Email, @Gander)"))
            {

                cmd.Connection = con;   
                cmd.Parameters.Add("@Name", txtfname.Text);
                cmd.Parameters.Add("@Fullname", txtfname.Text);
                cmd.Parameters.Add("@Password", txtpass.Text);
                cmd.Parameters.Add("@Email", txtemail.Text);
                cmd.Parameters.Add("@Gander", comboBox1.GetItemText(comboBox1.SelectedItem));

                con.Open()
                if(cmd.ExecuteNonQuery() > 0) 
                {
                   MessageBox.Show("Record inserted"); 
                }
                else
                {
                   MessageBox.Show("Record failed");
                }
            }
        }
        catch (Exception e)
        {
            MessageBox.Show("Error during insert: " + e.Message);
        }
    }
}

Answer 2

private void comboBox2_SelectedIndexChanged(object sender, EventArgs e) 
            { 
                SqlCommand cmd = new SqlCommand("insert into customer (name,weight,height,add_class,gender,fees) values(@name,@weight,@height,@add_class,@gender,@fees)", con); 
                cmd.Parameters.AddWithValue("name", this.textBox1.Text); 
                if (con.State == ConnectionState.Closed) 
                con.Open(); 
                cmd.ExecuteNonQuery(); 
                con.Close(); 
            }

Answer 3

The comments are getting a bit busy, so this is the sort of thing you need to do (including parameterising the query):

Specifically, you don't need a reader for an insert statement as it doesn't return a result set.

private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
    var sql = "insert into dbo.customer ...";
    using (var con = new SqlConnection(ss))
    {

        var cmd = new SqlCommand(sql , con);
        con.Open();
        cmd.ExecuteScalar();
        MessageBox.Show("Welcome to our gym");
    }
}

Answer 4

Hi check that customer table is available in gym Database. else try this link

Answer 5

I found that your connection string declaration is wrong

public string ss = "Data Source=D\\SQLEXPRESS;Initial Catalog=gym;Integrated Security=True";

need to update like below

public string ss = "Data Source=abc\\SQLEXPRESS;Initial Catalog=gym; user id=sa; Password=123456";

Data source will be not be D, It should be Server name.

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